#include <iostream>
#include <fstream>

using namespace std;
int M,N,v[16][16],St,S,i,j;
int main()
{
    fstream f( "flip.in",ios::in );
    fstream g( "flip.out",ios::out );
    f >> N >> M;
    for ( i=0 ; i<N ; i++ )
        for ( j=0 ; j<M ; j++ )
            f >> v[i][j];
    for ( i=0 ; i<N ; i++ )
        {
        S=0;
        for ( j=0 ; j<M ; j++ )
            S=S+v[i][j];
        if ( S<0 )
            for ( j=0 ; j<M ; j++ )
                v[i][j]=v[i][j]*(-1);
        }
    for ( j=0 ; j<M ; j++ )
        {
        S=0;
        for ( i=0 ; i<N ; i++ )
            S=S+v[i][j];
        if ( S<0 )
            for ( i=0 ; i<N ; i++ )
                v[i][j]=v[i][j]*(-1);
        }
    for ( i=0 ; i<N ; i++ )
        {
        S=0;
        for ( j=0 ; j<M ; j++ )
            S=S+v[i][j];
        if ( S<0 )
            {
            for ( j=0 ; j<M ; j++ )
                v[i][j]=v[i][j]*(-1);
            S=S*(-1);
            }
        St=St+S;
        }
    g << St;
    return 0;
}