CF2082A.Binary Matrix

传统题 时间 2000 ms 内存 256 MiB 3 尝试 1 已通过 1 标签

Binary Matrix

A matrix is called binary if all its elements are either 00 or 11.

Ecrade calls a binary matrix AA good if the following two properties hold:

  • The bitwise XOR of all numbers in each row of matrix AA is equal to 00.
  • The bitwise XOR of all numbers in each column of matrix AA is equal to 00.

Ecrade has a binary matrix of size nmn \cdot m. He is interested in the minimum number of elements that need to be changed for the matrix to become good.

However, it seems a little difficult, so please help him!

Input

Each test contains multiple test cases. The first line contains the number of test cases tt (1t4001 \le t \le 400). The description of the test cases follows.

The first line of each test case contains two integers n,mn, m (1n,m1001 \le n, m \le 100).

This is followed by nn lines, each containing exactly mm characters consisting only of 00 and 11, describing the elements of Ecrade's matrix.

It is guaranteed that the sum of nmn \cdot m across all test cases does not exceed 51045 \cdot 10^4.

Output

For each test case, output a single integer, the minimum number of elements that need to be changed.

Note

In the first test case, he needs to change 2 elements to obtain the following matrix $\begin{pmatrix}1&1&0\\1&0&1\\0&1&1\end{pmatrix}$.

In the second test case, he can make no changes to obtain the following matrix $\begin{pmatrix}0&0&0\\0&0&0\\0&0&0\end{pmatrix}$.

In the third test case, he needs to change 3 elements to obtain the following matrix $\begin{pmatrix}1&0&1\\0&0&0\\1&0&1\end{pmatrix}$.

Samples

7
3 3
010
101
010
3 3
000
000
000
3 3
100
010
001
3 3
101
010
000
3 3
000
010
000
1 4
0101
4 1
0
1
0
1
2
0
3
3
1
2
2

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