#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[])
{
    int n, m, **mat;
    unsigned int i, j, k;
    int max = 0;
    freopen("flip.in", "r", stdin);
    freopen("flip.out", "w", stdout);

    scanf("%d %d", &n, &m);
    mat = malloc((n + 1) * sizeof(*mat));
    for (i = 0; i < n; i ++) {
        mat[i] = malloc((m + 1) * sizeof(*mat[i]));
    }

    for (i = 0; i < n; i ++) {
        for (j = 0; j < m; j ++) {
            scanf("%d", &mat[i][j]);
        }
    }

    for (i = 0; i < ((1 << (n + m)) - 1); i ++)
    {
        int sum = 0;
        for (j = 0; j < n; j ++) {
            for (k = 0; k < n; k ++) {
                int flip_line = i & (1 << j) ? 1 : 0,
                    flip_col = i & (1 << (n + k)) ? 1 : 0;

                if (flip_col ^ flip_line)
                    sum -= mat[j][k];
                else
                    sum += mat[j][k];
            }
        }

        if (sum > max)
            max = sum;
    }

    printf("%d\n", max);
    return 0;
}