#include <fstream>
#include <iostream>
using namespace std;

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

int maxx, a[20][20], st[18], iuz[18], n, m,nr, sol, s;

void backk ()
{
    int sum = 0;
    for(int i = 1; i <= n; ++i)
    {
        int linie = 0;
        for(int j = 1; j <= m; ++j)
        {
            linie += ((iuz[j]) ? -1 : 1) * a[i][j];
        }
        sum += max(linie, -linie);
    }
    sol = max(sol, max(-sum, sum));

    for(int i = st[ st[ 0 ] ] + 1; i <= m; ++i)
    {
        st[ ++st[ 0 ] ]=i;
        iuz[ i ] = 1;
        backk();
        st[ st[ 0 ] ]=0;
        iuz[ i ] = 0;
        --st[ 0 ];
    }
}

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