#include <fstream>
#include <algorithm>

using namespace std;

ifstream f("flip.in");
ofstream g("flip.out");

int i, j, N, M, maxim, sum;
int v[20][20];

int main(){
    f >> N >> M;
    for (i = 1; i <= N; i++){
        for (j = 1; j <= M; j++)
            f >> v[i][j];
    }
    for (i = 1; i <= N; i++){
        sum = 0;
        for (j = 1; j <= M; j++)
            sum += v[i][j];
        if (sum < 0){
            maxim -= sum;
            for (j = 1; j <= M; j++)
                v[i][j] = -v[i][j];
        }
        else
            maxim += sum;
    }
    for (j = 1; j <= M; j++){
        sum = 0;
        for (i = 1; i <= N; i++)
            sum += v[i][j];
        if (sum < 0)
            maxim -= 2 * sum;
    }
    g << maxim;

    return 0;
}