#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;
        for (int j = 1; j <= n; ++j)
        {
            int sum=0;
            for (int k=0; k<m; k++)
                if((ci>>k)&1==1)
                {
                    if (a[j][k+1]>0)sum+=a[j][k+1];
                    else sum-=a[j][k+1];
                }
            if (sum>0&&sum>SUM)SUM=sum;
            else if (sum<0&&sum*(-1)>SUM)SUM=(-1)*sum;
        }
    }
    printf("%d\n",SUM);
    return 0;
}