#include <bits/stdc++.h>
using namespace std;
int n, m, v[20][20], col[20], mx=-2000000000;
void f(int k){
  int sum, i, j;
  sum=0;
  for(i=1; i<=m; i++)
    sum+=abs(col[i]);
  mx=max(mx, sum);
  for(i=k+1; i<=n; i++){
    for(j=1; j<=m; j++){
      v[i][j]=-v[i][j];
      col[j]+=2*v[i][j];
    }
    f(i);
    for(j=1; j<=m; j++){
      v[i][j]=-v[i][j];
      col[j]+=2*v[i][j];
    }
  }
}
int main(){
  ifstream fin ("flip.in");
  ofstream fout ("flip.out");
  int i, j;
  fin>>n>>m;
  for(i=1; i<=n; i++)
    for(j=1; j<=m; j++){
      fin>>v[i][j];
      col[j]+=v[i][j];
    }
  f(0);
  fout<<mx<<"\n";
  return 0;
}