#include <fstream>
using namespace std;

ifstream is("flip.in");
ofstream os("flip.out");

int n, m, a[20][20], b[20][20];
bool l[20];
int sum, sum2;

int main()
{
    is >> n >> m;
    for( int i = 1; i <= n; ++i )
        for( int j = 1; j <= m; ++j )
            is >> a[i][j];
    for( int j = 1; j <= m; ++j )
    {
        sum2 = 0;
        sum = 0;
        for( int i = 1; i <= n; ++i )
        {
            sum2 -= a[i][j];
            sum += a[i][j];
        }
        if( sum2 > sum )
            for( int i = 1; i <= n; ++i )
                b[i][j] = -a[i][j];
        else
            for( int i = 1; i <= n; ++i )
                b[i][j] = a[i][j];
    }
    sum = 0;
    for( int i = 1; i <= n; ++i )
        for( int j = 1; j <= m; ++j )
            sum += b[i][j];
    os << sum << ' ';
    is.close();
    os.close();
    return 0;
}