#include <fstream>

using namespace std;

ifstream fin("flip.in");
ofstream fout("flip.out");
int n, m, v[20][20], st[20];
long long sol = -1e6 * 20 * 20;
void bestsum( int k)
{
    int a[20][20], i, j;
    for ( i = 1; i <= n; ++i )
        for ( j = 1; j <= m; ++j )
            a[i][j] = v[i][j];

    for ( i = 1; i <= k; ++i )
        for ( j = 1; j <= m; ++j )
            a[st[i]][j] = -a[st[i]][j];
    long long rasp = 0;
    for ( j = 1; j <= m; ++j )
    {
        long long s = 0;
        for ( i = 1; i <= n; ++i )
            s += a[i][j];
        if ( s < 0 )
            s = -s;
        rasp += s;
    }

    sol = max(sol, rasp);
}
void Back( int k )
{
    int i;
    for ( i = st[k - 1] + 1; i <= n; ++i )
    {
        st[k] = i;
        bestsum( k );
        Back(k + 1);
    }
}
int main()
{
    fin >> n >> m;

    int i, j;
    for ( i = 1; i <= n; ++i )
        for ( j = 1; j <= m; ++j )
            fin >> v[i][j];

    Back(1);
    fout << sol << '\n';
    return 0;
}