diff --git a/youngjin.han/learning-node02-2020.org b/youngjin.han/learning-node02-2020.org
index 7139687..965c090 100644
--- a/youngjin.han/learning-node02-2020.org
+++ b/youngjin.han/learning-node02-2020.org
@@ -1,3 +1,19 @@
+* 2020-05-27
+*** Python #5:
+**** DONE Lecture content
+     CLOSED: [2020-05-27 수 22:30]
+     - Same structure as "Python #2"
+     - Exercises 27-31
+**** Lecture material
+     - Available on https://cloud.ungleich.ch/s/435FyfrQyEq6oF3
+* 2020-05-25
+*** Python #4:
+**** DONE Lecture content
+     CLOSED: [2020-05-27 수 22:41]
+     - Same structure as "Python #2"
+     - Exercises 23-26
+**** Lecture material
+     - Available on https://cloud.ungleich.ch/s/435FyfrQyEq6oF3
 * 2020-05-22
 **** DONE Lecture content
      CLOSED: [2020-05-23 토 00:21]
diff --git a/youngjin.han/python-the-hard-way/ex23.py b/youngjin.han/python-the-hard-way/ex23.py
new file mode 100644
index 0000000..2c84407
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/ex23.py
@@ -0,0 +1,23 @@
+import sys
+script, input_encoding, error = sys.argv
+
+
+def main(language_file, encoding, errors):
+    line = language_file.readline()
+
+    if line:
+        print_line(line, encoding, errors)
+        return main(language_file, encoding, errors)
+
+
+def print_line(line, encoding, errors):
+    next_lang = line.strip()
+    raw_bytes = next_lang.encode(encoding, errors=errors)
+    cooked_string = raw_bytes.decode(encoding, errors=errors)
+
+    print(raw_bytes, "<===>", cooked_string)
+
+
+languages = open("languages.txt", encoding="utf-8")
+
+main(languages, input_encoding, error)
diff --git a/youngjin.han/python-the-hard-way/ex24.py b/youngjin.han/python-the-hard-way/ex24.py
new file mode 100644
index 0000000..ca939a1
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/ex24.py
@@ -0,0 +1,43 @@
+print("Let's practice everything.") # print a script
+print('You\'d need to know \'bout escapes with \\ that do:') # print a script
+print('\n newlines and \t tabs.') # print a script
+
+# define a string array
+poem = """
+\tThe lovely world
+with logic so firmly planted
+cannot discern \n the needs of love
+nor comprehend passion from intuition
+and requires an explanation
+\n\t\twhere there is none.
+"""
+
+print("--------------") # print a script
+print(poem) # print a script
+print("--------------") # print a script
+
+
+five = 10 - 2 + 3 - 6 # calculate a number
+print(f"This should be five: {five}") # print a script
+
+def secret_formula(started): # define a function
+    jelly_beans = started * 500 # calculate a number
+    jars = jelly_beans / 1000 # calculate a number
+    crates = jars / 100 # calculate a number
+    return jelly_beans, jars, crates # return values
+
+
+start_point = 10000 # define a value
+beans, jars, crates = secret_formula(start_point) # run a function
+
+# remember that this is another way to format a string
+print("With a starting point of: {}".format(start_point)) # print a script
+# it's just like with an f"" string
+print(f"We'd have {beans} beans, {jars} jars, and {crates} crates.") # print a script
+
+start_point = start_point / 10 # calculate a number
+
+print("We can also do that this way:") # print a script
+formula = secret_formula(start_point) # run a function
+# this is an easy way to apply a list to a format string
+print("We'd have {} beans, {} jars, and {} crates.".format(*formula)) # print a script
diff --git a/youngjin.han/python-the-hard-way/ex25.py b/youngjin.han/python-the-hard-way/ex25.py
new file mode 100644
index 0000000..1c01fd8
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/ex25.py
@@ -0,0 +1,35 @@
+def break_words(stuff):
+    """This function will break up words for us."""
+    words = stuff.split(' ')
+    return words
+
+def sort_words(words):
+    """Sorts the words."""
+    return sorted(words)
+
+def print_first_word(words):
+    """Prints the first word after popping it off."""
+    word = words.pop(0)
+    print(word)
+
+def print_last_word(words):
+    """Prints the last word after popping it off."""
+    word = words.pop(-1)
+    print(word)
+
+def sort_sentence(sentence):
+    """Takes in a full sentence and returns the sorted words."""
+    words = break_words(sentence)
+    return sort_words(words)
+
+def print_first_and_last(sentence):
+    """Prints the first and last words of the sentence."""
+    words = break_words(sentence)
+    print_first_word(words)
+    print_last_word(words)
+
+def print_first_and_last_sorted(sentence):
+    """Sorts the words then prints the first and last one."""
+    words = sort_sentence(sentence)
+    print_first_word(words)
+    print_last_word(words)
diff --git a/youngjin.han/python-the-hard-way/ex26.py b/youngjin.han/python-the-hard-way/ex26.py
new file mode 100644
index 0000000..72d3252
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/ex26.py
@@ -0,0 +1,101 @@
+import sys
+
+print("How old are you?", end=' ')
+age = input()
+print("How tall are you?", end=' ')
+height = input()
+print("How much do you weigh?", end=' ')
+weight = input()
+
+print(f"So, you're {age} old, {height} tall and {weight} heavy.")
+
+script, filename = sys.argv
+
+txt = open(filename)
+
+print("Here's your file {filename}:")
+print(txt.read())
+
+print("Type the filename again:")
+file_again = input("> ")
+
+txt_again = open(file_again)
+
+print(txt_again.read())
+
+
+print("Let's practice everything.")
+print("""You\'d need to know \'bout escapes 
+      with \\ that do \n newlines and \t tabs.""")
+
+poem = """
+\tThe lovely world
+with logic so firmly planted
+cannot discern \n the needs of love
+nor comprehend passion from intuition
+and requires an explanation
+\n\t\twhere there is none.
+"""
+
+print("--------------")
+print(poem)
+print("--------------")
+
+
+five = 10 - 2 + 3 - 6
+print(f"This should be five: {five}")
+
+def secret_formula(started):
+    jelly_beans = started * 500
+    jars = jelly_beans / 1000
+    crates = jars / 100
+    return jelly_beans, jars, crates
+
+
+start_point = 10000
+beans, jars, crates = secret_formula(start_point)
+
+# remember that this is another way to format a string
+print("With a starting point of: {}".format(start_point))
+# it's just like with an f"" string
+print(f"We'd have {beans} beans, {jars} jars, and {crates} crates.")
+
+start_point = start_point / 10
+
+print("We can also do that this way:")
+formula = secret_formula(start_point)
+# this is an easy way to apply a list to a format string
+print("We'd have {} beans, {} jars, and {} crates.".format(*formula))
+
+
+
+people = 20
+cats = 30
+dogs = 15
+
+
+if people < cats:
+    print ("Too many cats! The world is doomed!")
+
+if people < cats:
+    print("Not many cats! The world is saved!")
+
+if people < dogs:
+    print("The world is drooled on!")
+
+if people > dogs:
+    print("The world is dry!")
+
+
+dogs += 5
+
+if people >= dogs:
+    print("People are greater than or equal to dogs.")
+
+if people <= dogs:
+    print("People are less than or equal to dogs.")
+
+
+if people == dogs:
+    print("People are dogs.")
+
diff --git a/youngjin.han/python-the-hard-way/ex29.py b/youngjin.han/python-the-hard-way/ex29.py
new file mode 100644
index 0000000..5e7eb6d
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/ex29.py
@@ -0,0 +1,32 @@
+people = 20
+cats = 30
+dogs = 15
+
+
+if people < cats:
+    print("Too many cats! The world is doomed!")
+
+if people > cats:
+    print("Not many cats! The world is saved!")
+
+if people < dogs:
+    print("The world is drooled on!")
+
+if people > dogs:
+    print("The world is dry!")
+
+if people != dogs:
+    print("People are not dogs.")
+
+dogs += 5
+
+if people >= dogs:
+    print("People are greater than or equal to dogs.")
+
+if people <= dogs:
+    print("People are less than or equal to dogs.")
+
+
+if people == dogs:
+    print("People are dogs.")
+    
diff --git a/youngjin.han/python-the-hard-way/ex30.py b/youngjin.han/python-the-hard-way/ex30.py
new file mode 100644
index 0000000..2e84c1c
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/ex30.py
@@ -0,0 +1,28 @@
+people = 3 # define a value
+cars = 4 # define a value
+trucks = 1 #define a value
+
+
+if cars > people: # test a criteria
+    print("We should take the cars.") # print a script
+elif cars < people: # test a criteria
+    print("We should not take the cars.") # print a script
+else: # test a criteria
+    print("We can't decide.") # print a script
+
+if trucks > cars: # test a criteria
+    print("That's too many trucks.") # print a script
+elif trucks < cars: # test a criteria
+    print("Maybe we could take the trucks.") # print a script
+else: # test a criteria
+    print("We still can't decide.") # print a script
+
+if people > trucks: # test a criteria
+    print("Alright, let's just take the trucks.") # print a script
+else: # test a criteria
+    print("Fine, let's stay home then.") # print a script
+
+if cars > people or trucks < cars: # test a criteria
+    print("There are a lot of cars") # print a script
+else: # test a criteria
+    print("There are a few cars") # print a script
diff --git a/youngjin.han/python-the-hard-way/ex31-1.py b/youngjin.han/python-the-hard-way/ex31-1.py
new file mode 100644
index 0000000..7284cc6
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/ex31-1.py
@@ -0,0 +1,20 @@
+from random import *
+
+print("""Please, Press 'Enter' on your keyboard to roll a dice.""")
+dumy = input("> ")
+dice = randint(1, 6)
+
+print("""Guess the dice number. and then,
+Please, Input it.""")
+your_number = input("> ")
+
+if int(your_number) > 6:
+    print("WRONG NUMBER!!!!")
+else:
+    if int(your_number) > dice:
+        print(f"Your number is bigger than dice is {dice}")
+    elif int(your_number) == dice:
+        print(f"Your number is equal to dice is {dice}")
+    elif int(your_number) < dice:
+        print(f"Your number is less than dice is {dice}")
+        
diff --git a/youngjin.han/python-the-hard-way/ex31.py b/youngjin.han/python-the-hard-way/ex31.py
new file mode 100644
index 0000000..625d012
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/ex31.py
@@ -0,0 +1,41 @@
+print("""You enter a dark room with two doors.
+Do you go through door #1 or door #2?""")
+
+door = input("> ")
+
+if door == "1":
+    print("There's a giant bear here eating a cheese cake.")
+    print("What do you do?")
+    print("1. Take the cake.")
+    print("2. Scream at the bear.")
+    print("3. Call 911.")
+
+    bear = input("> ")
+
+    if bear == "1":
+        print("The bear eats your face off. Good job!")
+    elif bear == "2":
+        print("The bear eats your legs off. Good job!")
+    elif bear == "3":
+        print("The bear eats your arms off. Good job!")
+    else:
+        print(f"Well, doing {bear} is probably better.")
+        print("Bear runs away.")
+
+elif door == "2":
+    print("You stare into the endless abyss at Cthulhu's retina.")
+    print("1. Blueberries.")
+    print("2. Yellow jacket clothespins.")
+    print("3. Understanding revolvers yelling melodies.")
+
+    insanity = input("> ")
+
+    if insanity == "1" or insanity == "2":
+        print("Your body survives powered by a mind of jello.")
+        print("Good job!")
+    else:
+        print("The insanity rots your eyes into a pool of muck.")
+        print("Good job!")
+
+else:
+    print("You stumble around and fall on a knife and die. Good job!")
diff --git a/youngjin.han/python-the-hard-way/exercise26.txt b/youngjin.han/python-the-hard-way/exercise26.txt
new file mode 100644
index 0000000..d7aaa3a
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/exercise26.txt
@@ -0,0 +1,98 @@
+print("How old are you?", end=' ')
+age = input()
+print("How tall are you?", end=' ')
+print("How much do you weigh?", end=' '
+weight = input()
+
+print(f"So, you're {age} old, {height} tall and {weight} heavy.")
+
+script, filename = argv
+
+txt = open(filenme)
+
+print("Here's your file {filename}:")
+print(tx.read())
+
+print("Type the filename again:")
+file_again = input("> ")
+
+txt_again = open(file_again)
+
+print(txt_again_read())
+
+
+print('Let's practice everything.')
+print('You\'d need to know \'bout escapes 
+      with \\ that do \n newlines and \t tabs.')
+
+poem = """
+\tThe lovely world
+with logic so firmly planted
+cannot discern \n the needs of love
+nor comprehend passion from intuition
+and requires an explanation
+\n\t\twhere there is none.
+"""
+
+print("--------------)
+print(poem)
+print(--------------")
+
+
+five = 10 - 2 + 3 - 
+print(f"This should be five: {five}"
+
+def secret_formula(started)
+    jelly_beans = started * 500
+    jars = jelly_beans / 1000
+    crates = jars  100
+    return jelly_beans, jars, crates
+
+
+start_point = 10000
+beans, jars = secret_formula(start_point)
+
+# remember that this is another way to format a string
+print("With a starting point of: {}".format(start_point))
+# it's just like with an f"" string
+print(f"We'd have {beans} beans, {jars} jars, and {crates} crates.")
+
+start_point = start_point / 10
+
+print("We can also do that this way:")
+formula = secret_formula(startpoint)
+# this is an easy way to apply a list to a format string
+print("We'd have {} beans, {} jars, and {} crates.".format(*formula))
+
+
+
+people = 20
+cates = 30
+dogs = 15
+
+
+if people < cats:
+    print "Too many cats! The world is doomed!"
+
+if people < cats:
+    print("Not many cats! The world is saved!")
+
+if people < dogs:
+    print("The world is drooled on!")
+
+if people > dogs
+    print("The world is dry!")
+
+
+dogs += 5
+
+if people >= dogs:
+    print("People are greater than or equal to dogs.")
+
+if people <= dogs
+    print("People are less than or equal to dogs.)
+
+
+if people = dogs:
+    print("People are dogs.")
+
diff --git a/youngjin.han/python-the-hard-way/languages.txt b/youngjin.han/python-the-hard-way/languages.txt
new file mode 100644
index 0000000..6d47317
--- /dev/null
+++ b/youngjin.han/python-the-hard-way/languages.txt
@@ -0,0 +1,97 @@
+Afrikaans
+አማርኛ
+Аҧсшәа
+العربية
+Aragonés
+Arpetan
+Azərbaycanca
+Bamanankan
+বাংলা
+Bân-lâm-gú
+Беларуская
+Български
+Boarisch
+Bosanski
+Буряад
+Català
+Чӑвашла
+Čeština
+Cymraeg
+Dansk
+Deutsch
+Eesti
+Ελληνικά
+Español
+Esperanto
+فارسی
+Français
+Frysk
+Gaelg
+Gàidhlig
+Galego
+한국어
+Հայերեն
+हिन्दी
+Hrvatski
+Ido
+Interlingua
+Italiano
+עברית
+ಕನ್ನಡ
+Kapampangan
+ქართული
+Қазақша
+Kreyòl ayisyen
+Latgaļu
+Latina
+Latviešu
+Lëtzebuergesch
+Lietuvių
+Magyar
+Македонски
+Malti
+मराठी
+მარგალური
+مازِرونی
+Bahasa Melayu
+Монгол
+Nederlands
+नेपाल भाषा
+日本語
+Norsk bokmål
+Nouormand
+Occitan
+Oʻzbekcha/ўзбекча
+ਪੰਜਾਬੀ
+پنجابی
+پښتو
+Plattdüütsch
+Polski
+Português
+Română
+Romani
+Русский
+Seeltersk
+Shqip
+Simple English
+Slovenčina
+کوردیی ناوەندی
+Српски / srpski
+Suomi
+Svenska
+Tagalog
+தமிழ்
+ภาษาไทย
+Taqbaylit
+Татарча/tatarça
+తెలుగు
+Тоҷикӣ
+Türkçe
+Українська
+اردو
+Tiếng Việt
+Võro
+文言
+吴语
+ייִדיש
+中文
diff --git a/youngjin.han/python.org b/youngjin.han/python.org
index 020c3c6..6830728 100644
--- a/youngjin.han/python.org
+++ b/youngjin.han/python.org
@@ -1,3 +1,27 @@
+* 2020-05-27
+** note
+   - ex27.py
+     - none
+   - ex28.py
+     - <= (greater than or equal to), =< (less than or equal t0)
+   - ex29.py
+     - The 'if' means to test criteria.
+     - The 'if' processes the script is intended.
+     - If the script is not indented, an error should be occured.
+   - ex30.py
+     - none
+   - ex31.py
+     - none
+* 2020-05-25
+** note
+   - ex23.py
+     - none
+   - ex24.py
+     - none
+   - ex25.py
+     - none
+   - ex26.py
+     - none
 * 2020-05-22
 ** note
    - ex15.py