#include<iostream>
#include<fstream>
using namespace std;

ifstream ifile;
ofstream ofile;
int a,b,i,j,best=0,m[20][16],bk[20];
    
void resolve(){
     int x,s=0;
     for(j=1;j<=b;j++){
            x=0;
            for(i=1;i<=a;i++){
                  x = x + bk[i]*m[i][j];
            }
            if(x<0) s -= x;
            else s += x;
     }
     if(s>best) best = s;
}

void bktr(int k){
     if(k==a+1) resolve();
     else {
                bk[k] = -1;
                bktr(k+1);
                bk[k] = 1;
                bktr(k+1);
          }
}

int main(){
    ifile.open("flip.in");
    ifile>>a>>b;
    for(i=1; i<=a; i++){
            for(j=1; j<=b; j++){
                    ifile>>m[i][j];
                    best += m[i][j];
            }
    }
    ifile.close();
    
    bktr(1);

    ofile.open("flip.out");
    ofile<<best;
    ofile.close();
    return 0;   
}