#include <bits/stdc++.h>

using namespace std;

ifstream fin("flip.in");
ofstream fout("flip.out");
int a[20][20],b[20],s1,s,smax=INT_MIN,n,m;
int main()
{
    int i,j;
    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;

    return 0;
}