#include <fstream>

using namespace std;
ifstream f("flip.in");
ofstream g("flip.out");

int a[25][25], rez = 0, n, m, st[25*25];
void tip()
{
    int s1 = 0, s2 = 0;
    for(int i = 1; i <= n; i++)
    {
        s1 = 0;
        for(int j = 1; j <= m; j++)
            s1 += st[j] * a[i][j];
        if(s1 < 0)
            s1 = -s1;
        s2 += s1;
    }
    if(s2 > rez)
        rez = s2;
}
void bk(int k)
{
    if(k > n && k > m)
        tip();
    else
    {
        st[k] = 1;
        bk(k + 1);
    }
}

int main()
{
    f >> n >> m;
    for(int i = 1; i <= n; i++)
        for(int j = 1; j <= m; j++)
            f >> a[i][j];
    bk(1);
    g << rez;
    return 0;
}