#include <iostream>
#include <fstream>

using namespace std;
int M,N,v[16][16],Sp,Sn,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++ )
        {
        Sp=0;
        Sn=0;
        for ( j=0 ; j<M ; j++ )
            {
            if ( v[i][j]>0 )
                Sp=Sp+v[i][j];
            if ( v[i][j]<0 )
                Sn=Sn+v[i][j]*(-1);
            }
        if ( Sn>Sp )
            for ( j=0 ; j<M ; j++ )
                v[i][j]=v[i][j]*(-1);
        }
    for ( j=0 ; j<M ; j++ )
        {
        Sp=0;
        Sn=0;
        for ( i=0 ; i<N ; i++ )
            {
            if ( v[i][j]>0 )
                Sp=Sp+v[i][j];
            if ( v[i][j]<0 )
                Sn=Sn+v[i][j]*(-1);
            }
        if ( Sn>Sp )
            for ( i=0 ; i<N ; i++ )
                v[i][j]=v[i][j]*(-1);
        }
    for ( i=0 ; i<N ; i++ )
        {
        Sp=0;
        Sn=0;
        for ( j=0 ; j<M ; j++ )
            {
            if ( v[i][j]>0 )
                Sp=Sp+v[i][j];
            if ( v[i][j]<0 )
                Sn=Sn+v[i][j]*(-1);
            }
        if ( Sn>Sp )
            for ( j=0 ; j<M ; j++ )
                v[i][j]=v[i][j]*(-1);
        S=S+Sp-Sn;
        }
    g << S;
    return 0;
}