diff --git a/birthdayparadox.py b/birthdayparadox.py
index 5ef7412..2a06ece 100644
--- a/birthdayparadox.py
+++ b/birthdayparadox.py
@@ -1,4 +1,4 @@
-""" Birthday Paradox Simulation, by Al Sweigart al@inventwithpython.com
+"""Birthday Paradox Simulation, by Al Sweigart al@inventwithpython.com
 Explore the surprising possibilities of the "Birthday Paradox".
 More info at https://en.wikipedia.org/wiki/Birthday_problem
 View this code at https://nostarch.com/big-book-small-python-projects
@@ -6,6 +6,7 @@ Tags: short, math, simulation"""
 
 import datetime, random
 
+
 def getBirthdays(numberOfBirthdays):
     """Returns a list of number random date objects for birthdays."""
     birthdays = []
@@ -20,4 +21,49 @@ def getBirthdays(numberOfBirthdays):
         birthdays.append(birthday)
     return birthdays
 
-    
\ No newline at end of file
+def getMatch(birthdays):
+    """Returns the date object of a birthday that occurs more than once
+    in the birthdays list."""
+    if len(birthdays) == len(set(birthdays)):
+        return None #All birthdays are unique, so return None. 
+
+    # Compare each birthday to every other birthday:
+    for a, birthdayA in enumerate(birthdays):
+        for b, birthdayB in enumerate(birthdays[a + 1 :]):
+            if birthdayA == birthdayB:
+                return birthdayA # Return the matching birthday
+
+# Display the intro:
+print('''Birthday Paradox, by Al Sweigart al@inventwithpython.com
+The Birthday Paradox shows us that in a group of N people, the odds
+that two of them have matching birthdays is surprisingly large.
+This program does a Monte Carlo simulation (that is, repeated random
+simulations) to explore this concept.
+
+(It's not actually a paradox, it's just a surprising result.)
+''')
+# Set up a tuple of month names in order:
+MONTHS = ('Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 
+        'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec')
+
+while True: # Keep asking until the user enters a valid amount. 
+    print('How many birthdays shall I generate (Max 100)')
+    response = input('> ')
+    if response.isdecimal() and (0 < int(response) <= 100):
+        numBDays = int(response)
+        break # User has entered a valid amount
+print()
+
+# Generate and display birthdays: 
+print('Here are', numBDays, 'birthdays:')
+birthdays = getBirthdays(numBDays)
+for i, birthday in enumerate(birthdays):
+    if i != 0:
+        # Display a comma for each birthday after the first birthday. 
+        print(', ', end='')
+    monthName = MONTHS[birthday.month - 1]
+    dateText = '{} {}'.format(monthName, match.day)
+    print(dateText, end='')
+print()
+print()
+