#!/usr/bin/python

x = open('Pneumotoulthamicrescopicfilicoloaganiconissis-df5bb3d8f83d6d37e16560062cb231bc.txt').read()
y = open('titin.txt').read()

out = ''
for a, b in zip(x,y):
    if a != b:
        out += a
        print out

print out