#include <fstream>
using namespace std;

ifstream fin("flip.in");
ofstream fout("flip.out");

int n, m, a[17][17];

void flip(int x, int y) {
    if(x)
        for(int i = 1; i <= m; ++i)
            a[x][i] *= -1;
    if(y)
        for(int i = 1; i <= n; ++i)
            a[i][y] *= -1;
}

int sum() {
    int s = 0;
    for(int i = 1; i <= n; ++i)
        for(int j = 1; j <= n; ++j)
            s += a[i][j];
    return s;
}

int abs(int n) {
    if(n < 0)
        return -n;
    return n;
}

int main() {
    fin >> n >> m;
    for(int i = 1; i <= n; ++i)
        for(int j = 1; j <= m; ++j)
            fin >> a[i][j];

    int lastSum = sum(), currentSum = lastSum;

    do {
        for(int i = 1; i <= n; ++i) {
            int s = 0;
            for(int j = 1; j <= m; ++j)
                s += a[i][j];
            if(-s > s)
            for(int j = 1; j <= m; ++j)
                a[i][j] *= -1;
        }
        for(int j = 1; j <= m; ++j) {
            int s = 0;
            for(int i = 1; i <= n; ++i)
                s += a[i][j];
            if(-s > s)
            for(int i = 1; i <= n; ++i)
                a[i][j] *= -1;
        }
        lastSum = currentSum;
        currentSum = sum();
    } while(abs(lastSum - currentSum) != 0);

    fout << currentSum;
}