#include <fstream>

using namespace std;
ifstream f("flip.in");
ofstream g("flip.out");

int n,m,i,j,k,Max=0;
int a[18][18];
int v[18];
int main()
{
    f >> n >> m;
    for(i=1;i<=n;i++)
        for(j=1;j<=m;j++)
            f >> a[i][j];

    while(v[0]==0){
        i=m;
        while(v[i]==1){
            v[i]=0;
            i--;
        }
        v[i]=1;
        int sum=0,sumr=0;
        for(j=1;j<=n;j++){
            sumr=0;
            for(k=1;k<=m;k++){
                if(v[k]){
                    sumr=sumr-a[j][k];
                }
                else
                    sumr=sumr+a[j][k];
            }
            if(sumr<0)
                sum-=sumr;
            else
                sum+=sumr;
        }
        Max=max(sum,Max);
    }
    g << Max;
    return 0;
}