#include<fstream>
using namespace std;
int n,m,i,j,a[18][18],v[18],s,s1,stot;
int main (){
    ifstream fin ("flip.in");
    ofstream fout ("flip.out");
    fin>>n>>m;
    for(i=1;i<=n;i++)
        for (j=1;j<=m;j++)
            fin>>a[i][j];

    while (v[0]==0){
        i=m;
        while (v[i]==1){
            v[i]=0;
            i--;
        }
        v[i]=1;
        s1=0;
        for (i=1;i<=n;i++){
            s=0;

            for (j=1;j<=m;j++){
                if (v[i]==1){
                    s-=a[i][j];
                }
                else
                    s+=a[i][j];
            }

            if (s > 0)
                s1 += s;
            else
                s1 -= s;

            if (s1 > stot)
                stot = s1;


        }

    }
    fout<<stot;
    return 0;
}