#include <bits/stdc++.h>
using namespace std;
int n,m,a[17][17],SUM;
int main()
{
    freopen("flip.in","r",stdin);
    freopen("flip.out","w",stdout);
    scanf("%d %d\n",&n,&m);
    for (int i = 1 ; i<=n ; ++i)
        for (int  j = 1 ; j <= m ; ++j)
            scanf("%d", &a[i][j]);
    for (int i = 1 ; i<(1<<m); ++i)
    {
        int ci=i;
        int ss=0;
        for (int j = 1; j <= n; ++j)
        {
            int sum=0;

            for (int k=0; k<m; k++)
                if((ci&(1<<k)))
                {
                    //if (a[j][k+1]>0)
                    //else sum-=a[j][k+1];
                    sum-=a[j][k+1];
                }
                else sum+=a[j][k+1];
            if (sum>0)ss+=sum;
            else ss-=sum;

        }
        if (ss>SUM)SUM=ss;
    }
    printf("%d\n",SUM);
    return 0;
}