#include<fstream>
using namespace std;

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

long long m, n, i, j, s, s1, s2, joc[1000][20];

int main() {
    fin >> n >> m;
    for (i = 1; i <= n; i++) {
        for (j = 1; j <= m; j++) {
            fin >> joc[i][j];
        }
    }
    fin.close();
    for (i = 1; i <= n; i++) {//comut pe Ox
        s1 =  s2 = 0;
        for (j = 1; j <= m; j++) {
            s1 += joc[i][j];
        }
        for (j = 1; j <= m; j++) {
            s2 += -joc[i][j];
        }
        if (s1 < s2) {
            for (j = 1; j <= m; j++) {
                joc[i][j] = -joc[i][j];
            }
        }
    }
    for (j = 1; j <= m; j++) {//comut pe Oy
        s1 = s2 = 0;
        for (i = 1; i <= n; i++) {
            s1 += joc[i][j];
        }
        for (i = 1; i <= n; i++) {
            s2 += -joc[i][j];
        }
        if (s1 < s2) {
            for (i = 1; i <= n; i++) {
                joc[i][j] = -joc[i][j];
            }
        }
    }
    for (i = 1; i <= n; i++) {
        for (j = 1; j <= m; j++) {
            s += joc[i][j];
        }
    }
    fout << s;
    fout.close();
    return 0;
}