#!/usr/bin/python3
# written by andrewt@unsw.edu.au as a COMP(2041|9044) example

# Check if we've seen a line read from stdin,
# using a dict.
# Print snap! if a line has been seen previously
# Exit if an empty line is entered

line_count = {}
while True:
    try:
        line = input("Enter line: ")
    except EOFError:
        break
    if line in line_count:
        print("Snap!")
    else:
        line_count[line] = 1