#include<fstream>
using namespace std;
int i, j, n, m, a[18][18], j2, j3, x[17], y[17], aux1, aux2, s, smax;
FILE*fin=fopen("flip.in","r");
ofstream fout("flip.out");
int main(){
    fscanf(fin,"%d%d", &n, &m);
    for(i=1; i<=n; i++)
        for(j=1; j<=m; j++)
            fscanf(fin,"%d", &a[i][j]);
    while(x[0]==0){
        j2=n;
        while(x[j2]==1){
            x[j2]=0;
            j2--;
        }
        //x[j2]++;
        y[0]=0;
        while(y[0]==0){
            j3=m;
            while(y[j3]==1){
                y[j3]=0;
                j3--;
            }
            //y[j3]++;
            s=0;
            for(aux1=1; aux1<=n; aux1++)
                for(aux2=1; aux2<=m; aux2++){
                    if(x[aux1]==y[aux2])
                        s+=a[aux1][aux2];
                    else
                        s-=a[aux1][aux2];
                }
            if(s>smax)
                smax=s;
                y[j3]++;
        }
        x[j2]++;
    }
    fout<<smax<<"\n";
return 0;
}