#include <bits/stdc++.h>

using namespace std;
ifstream fin("flip.in");
ofstream fout("flip.out");

int a[20][20], b[20], n,m;

int main()
{
    int i,j,s1,smax=INT_MIN,s;
    fin >> n >> m;
    for (i = 1; i <= n; i++)
        for (j=1; j<=m; j++)
            fin >> a[i][j];
    while (b[0]==0)
    {
        s1=0;
        for (i=1; i<=n; i++)
        {
            s=0;
            for (j=1; j<=m; j++)
                if (b[j]==1)
                    s-=a[i][j];
                else
                    s+=a[i][j];
            if (s<0) s1-=s;
            else s1+=s;
        }
        smax=max(smax,s1);
        for (i=m; b[i]==1; i--)
            b[i]=0;
        b[i]++;
    }
    fout << smax << "\n";

    return 0;
}