Hamming distance between two strings of equal length is the number of positions at which the corresponding symbols are different. You are given two strings; calculate the distance between them.

Input

The input consists of two lines. Each line contains a string of characters 'A'-'Z' between 1 and 100 characters, inclusive. The strings have equal length.

Output

Output Hamming distance between the strings.

见题面 Input 部分

见题面 Output 部分