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Problem 1733 Image Distortion

Accept: 266    Submit: 388
Time Limit: 1000 mSec    Memory Limit : 32768 KB

Problem Description

In the process of transmission, data loss may occur, resulting in image distortion and so on. To simplify the problem, we consider an image whose pixel is a single bit (0 or 1), and then the bit errors could be: 1 to 0 or 0 to 1.
You should calculate the total bit errors in the process of transmission.

Input

There are multiple test cases. For each test case, the first line contains two integers N and M (2≤N,M≤100), indicating the size of the image. The next N lines, each line contains M characters, these N*M characters indicate the image before transmission. The next N lines, each line contains M characters, these N*M characters indicate the image after transmission. The character is either 0 or 1.

Output

For each test case, output an integer indicating the total bit errors in the process of transmission.

Sample Input

7 7 0000000 0111110 0101010 0111110 0101010 0111110 0000000 0000000 0110110 0111010 0110110 0101010 0111110 0000000

Sample Output

3

Source

FZU 2009 Summer Training Qualification -- Hero Revival 3

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