#include <fstream>
using namespace std;
ifstream cin( "flip.in" );
ofstream cout( "flip.out" );
int s, a[ 17 ][ 17 ];
int lin[ 17 ];
int col[ 17 ];

int main()
{
    int n, m, l, c, ll, cc;
    cin >> n >> m;
    for( l = 0; l < n; l++ )
        for( c = 0; c < m; c++ ){
            cin >> a[ l ][ c ];
            col[ c ] += a[ l ][ c ];
            s += a[ l ][ c ];
        }
    int maxx = s;
    for( l = 0; l < m; l++ )
        if( col[ l ] < 0 ){
            col[ l ] = -col[ l ];
            for( c = 0; c < n; c++ )
                a[ c ][ l ] = -a[ c ][ l ];
        }
    for( l = 0; l < n; l++ )
        for( c = 0; c < m; c++ )
            lin[ l ] += a[ l ][ c ];
    s = 0;
    for( l = 0; l < m; l++ )
        s += col[ l ];
    maxx = max( s, maxx );

    for( l = 0; l < n; l++ )
        if( lin[ l ] < 0 )
            lin[ l ] = -lin[ l ];

    s = 0;
    for( l = 0; l < n; l++ )
        s += lin[ l ];
    maxx = max( s, maxx );

    cout << maxx;
    return 0;
}