#include <iostream>
#include <cmath>
#include <fstream>
using namespace std;
int v[20][20],i,j;

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

int suma(int v[20][20],int n,int m){
    int s=0;
   for (int i=1;i<=n;i++)
    for (int j=1;j<=m;j++)
        s+=v[i][j];
    return s;

}

int main(){

    int n,m,sumabarosana=INT_MIN;
    cin >>n>>m;
    int x[n+m+1]={0};

    for ( i=1;i<=n;i++)
        for ( j=1;j<=m;j++)
          cin >>v[i][j];
    int s;
    while (x[0]==0){
        s=0;
        for ( i=1;i<=n;i++){
            for ( j=1;j<=m;j++){
                if (x[j+n]==1 || x[i]==1){
                    if (x[j+n]==1 && x[i]==1){s+=v[i][j];}else{s-=v[i][j];}
                }
            }
        }
        sumabarosana=max(s,sumabarosana);

            for(i=m+n;x[i]==1;i--)
        {
            x[i]=0;
        }
        x[i]++;

    }
    cout <<sumabarosana;
}