#include <fstream>
using namespace std;

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

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

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

int suma(int a[17][17]) {
    int s=0;
    for (int i=1; i<=n; i++)
        for (int j=1; j<=m; j++)
            s+=a[i][j];
    return s;
}

void reset() {
    for (int i=1; i<=n; i++)
        for (int j=1; j<=m; j++)
            b[i][j]=a[i][j];
}

void flip1(int i) {
    for (int j=1; j<=m; j++)
        b[i][j]=-1*b[i][j];
}

void flip2(int j) {
    for (int i=1; i<=n; i++)
        b[i][j]=-1*b[i][j];
}

void copy() {
    for (int i=1; i<=n; i++)
        for (int j=1; j<=m; j++)
            a[i][j]=b[i][j];
}

int main()
{
    int s=0;

    citire();
    s = suma(a);
    for (int i=1; i<=n; i++){
        flip1(i);
        if(suma(b) > suma(a))
            copy();
        else
            reset();
    }
    for (int j=1; j<=m; j++) {
        flip2(j);
        if(suma(b) > suma(a))
            copy();
        else
            reset();
    }

    s = suma(a);
    fout << s;
    return 0;
}