#include<fstream>
#include<cstring>
using namespace std;
int n, m, i, j, jj, a[17][17], b[17][17], x[17], s, sc, sol;
ifstream in("flip.in");
ofstream out("flip.out");
int main(){
    in>>n>>m;
    for(i=1; i<=n; i++){
        for(j=1; j<=m; j++){
            in>>a[i][j];
        }
    }
    while(x[0]==0){
        memcpy(b, a, sizeof(b));
        s=0;
        sc=0;
        j=m;
        while(x[j]==1){
            x[j]=0;
            j--;
        }
        x[j]=1;
        for(jj=1; jj<=m; jj++){
            for(i=1; i<=n; i++)
                if(x[jj]==1)
                    b[i][jj]=-a[i][jj];
                else
                    b[i][jj]=a[i][jj];

        }
        for(i=1; i<=n; i++){
            sc=0;
            for(jj=1; jj<=m; jj++)
                sc+=b[i][jj];
            s+=sc>0?sc:-sc;
        }
        if(s>sol)
            sol=s;
    }
    out<<sol;
return 0;
}