The hamming distance between two bit-strings is the number of positions those bit-strings are different. Given two bit-strings you are asked to calculate the hamming distance between those two.

Input

The input contains two lines each one representing one of the two bit-strings. Both of the bit-strings are guaranteed to have the same length (1 ≤ |s1| = |s2| ≤ ).

Output

The program should print the hamming distance between those bit-strings.

Examples

Input

Output

100101
110111

2

Explanation

100101 and 110111 differ in positions (1-based) 2 and 5.