#include <bits/stdc++.h>
using namespace std;
ifstream fin ("flip.in");
ofstream fout ("flip.out");
int v [17][17], n, m,  mx = -1000000003;
bool flip [17];
int bestop (){
    int s = 0;
    for (int i = 1; i <= m; i ++){
        int S = 0 ;
        for (int j = 1; j <= n; j ++)
            if (flip [j])S += (0 - v [j][i]);
            else S += v [j][i];
        if (S > 0)s += S;
        else s += (0 - S);
    }
    return s;
}
int main (){
    fin >> n >> m;
    for (int i = 1; i <= n; i ++)
        for (int j = 1; j <= m ; j ++)
            fin >> v [i][j];
    for (int i = 1; i < (1 << n); i ++){
        for (int j = 0; (1 << j) <= i; j ++)
            if ((1 << j) & i)flip [j + 1] = 1;
            else flip [j + 1] = 0;
        mx = max (mx , bestop ());
    }
    fout << mx;
    return 0;
}