#include<bits/stdc++.h>
using namespace std;
ifstream fin("flip.in");
ofstream fout("flip.out");
int n,m,sum,sumx,a[20][20];
void calcul()
{
  int aux = 0;
  sumx = 0;
  for (int i=1;i<=n;i++)
   {
     aux = 0;
     for (int j=1;j<=m;j++)
      {
        aux += a[i][j];
      }
     if (aux < 0)
     {
       aux *= (-1);
     }
      sumx += aux;
   }
}
void bck(int k)
{
  if (k>m)
  {
    calcul();
    sum = max(sum,sumx);
  }
  else
  {
    bck(k+1);
    for (int i=1;i<=n;i++)
     a[i][k] *= (-1);
    bck(k+1);
  }
}
int main()
{
  fin>>n>>m;
  for (int i=1;i<=n;i++)
   for (int j=1;j<=m;j++)
    {
      fin>>a[i][j];
    }
  bck(1);
  fout<<sum<<'\n';
  return 0;
}