#include <cstdio>
using namespace std;const int DIM = 16;int a[DIM + 5][DIM + 5], aux[DIM + 5][DIM + 5];void copy(int n, int m){int i, j;for (i = 1; i <= n; i ++)for (j = 1; j <= m; j ++)aux[i][j] = a[i][j];}int solve(int n, int m, int s){int i, j;long long sum;for (j = 1; j <= m; j ++){sum = s;for (i = 1; i <= n; i ++)sum -=  2 * aux[i][j];if (sum > s){s = sum;for (i = 1; i <= n; i ++)aux[i][j] = -aux[i][j];}}return s;}int main(){freopen("flip.in", "r", stdin);freopen("flip.out", "w", stdout);int n, m, i, j, k, ns, s = 0, sum, max = -256000000;scanf("%d%d", &n, &m);for (i = 1; i <= n; i ++)for (j = 1; j <= m; j ++){scanf("%d", &a[i][j]);s += a[i][j];}ns = (1 << n) - 1;for (i = 1; i <= ns; i ++){copy(n, m);sum = s;for (j = 0; j < n; j ++)if ((1 << j) & i)for (k = 1; k <= m; k ++){sum -= 2 * aux[j + 1][k];aux[j + 1][k] = -aux[j + 1][k];}sum = solve(n, m, sum);max = max > sum ? max:sum;}printf("%d\n", max);return 0;}