#include <iostream>
#include <fstream>

using namespace std;

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

int n,m,a[20][20];
int main()
{
    fin >> n >> m;
    for(int i = 1; i <= n; i++)
        for(int j = 1; j <= m; j++)
            fin >> a[i][j];

    int smax = 0;
    for(int i = 0; i < (1 << n); i++)
    {
        int sum = 0;
        for(int j = 1; j <= n; j++)
        {
            int line = 0;
            for (int k = 1; k <= m; ++k)
            {
                line += a[j][k];
            }

            if (line < 0)
            {
                sum -= line;
            }
            else
            {
                sum += line;
            }
        }

        smax = (smax < sum) ? sum : smax;
    }

    fout << smax;
    return 0;
}