# The Problem
# You have 100 doors in a hallway in a row that are all initially closed. 
# You make 100 passes by the doors. The first time through, you visit every door and toggle the door (if the door is closed, you open it; if it is open, you close it). The second time you only visit every 2nd door (door #2, #4, #6, ...). The third time, every 3rd door (door #3, #6, #9, ...), etc, until you only visit the 100th door.

# Description
# Write a script that lists the number (the name) 
# of the open doors after you visited all the 100 doors 100 times. 
# This is an individual assignment but of course, you can get help from the others.

# Expected Console Output
# Of course, not 1, 2 and 3 is open in the end.
# user@computer:~$ python 100doors.py
# The following doors are open: 1, 2, 3