#include <limits.h>
#include <stdio.h>

#define SIZE 16

static int table[SIZE][SIZE], msum = INT_MIN;

static void check_sum(int n, int m)
{
    int i, j, aux;

    for (i = aux = 0; i < n; i++) {
        for (j = 0; j < m; j++) {
            aux += table[i][j];
        }
    }

    if (aux > msum) {
        msum = aux;
    }
}

static void subm(int n, int m)
{
    int i, j, k;

    for (i = 1; i < 1 << n; i++) {
        for (j = 0; j < n; j++) {
            if ((i >> j) & 1) {
                for (k = 0; k < m; k++) {
                    table[j][k] *= -1;
                }

                check_sum(n, m);
            }
        }
    }
}

int main(void)
{
    int n, m, i, j;

    freopen("flip.in", "r", stdin);
    freopen("flip.out", "w", stdout);

    scanf("%d %d", &n, &m);

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

    for (i = 0; i < m; i++) {
        for (j = 0; j < n; j++) {
            table[j][i] *= -1;
        }

        check_sum(n, m);

        subm(n, m);

        for (j = 0; j < n; j++) {
            table[j][i] *= -1;
        }
    }

    printf("%d", msum);

    return 0;
}