###Description

- Character recognition is the conversion of images into text. For now we consider each character in the picture is a N
*M matrix with only zeros and ones, and we need to recognize K characters. You are to write a program to find minimal number of pixels so that we can recognize each character.*3, we can think 'T' and 'L' are 111 100 010 100 010 111 so we can recognize the character with only bottom-left pixel, the answer is 1.

For example, we have only two characters 'T' and 'L', and the matrix size is 3

###Limits

- -Memory limit per test: 256 megabytes
- -Time limit per test: The faster the better

###Compile & Environment

- C++
- g++ Main.cc -o Main -fno-asm -Wall -lm --static -std=c++0x -DONLINE_JUDGE Java
- J2SE 8

Maximum stack size is 50m

### Input

- The first line of input is three integers N, M, K (1 <= N, M <= 10, 2 <= K <= 6). Which represents the size of matrix and number of characters. Then is following K blocks, which represents the matrix. Notice that each block starts with a blank line.

###Output

- You should output the minimum number of pixels, which is the answer.

###Sample Test

#### Input

2 3 2

111

010

100

100

####output

1