Czech Technical University in Prague

ACM ICPC sponsored by IBM

Central Europe Regional Contest 2007 - Practice Session

Hamming Distance

distance.c | distance.C | distance.java | distance.p

Have you ever heard of the Hamming distance. It is the number of positions for which the

corresponding digits differ. Your task is to write a program that computes this distance for two

binary strings.

Input Specification

The input contains several test cases. Each test case consists of two lines. Each line contains

one binary number. Any two numbers given in one test case have the same length, which is at

most 100 binary digits. The last test case is followed by a line containing the uppercase letter

"X".

Output Specification

Your program must output a single line for each test case. The line should contain the statement

"Hamming distance is X.", where X is the number of positions where the two numbers have

different digits.

Sample Input

0

1

000

000

1111111100000000

0000000011111111

101

000

X

Output for Sample Input

Hamming distance is 1.

Hamming distance is 0.

Hamming distance is 16.

Hamming distance is 2.