#include <fstream>
using namespace std;

const int NMAX = 16;

int n, m, sol = -NMAX * NMAX * 1000000;
int matrice[1 + NMAX][1 + NMAX];
int semn[1 + NMAX];

void back(int index)
{
  if(index <= n)
  {
    semn[index] = 1;
    back(index+1);
    semn[index] = -1;
    back(index+1);
  }
  else
  {
    int i, j, sCol, sum = 0;
    for(j = 1; j <= m; j++)
    {
	 sCol = 0;
      for(i = 1; i <= n; i++)
 {
    sCol += matrice[i][j] * semn[i];
 }

 if(sCol < 0)
   sum -= sCol;
 else
   sum += sCol;
    }

    if(sum > sol)
    {
      sol = sum;
    }
  }
}

int main()
{
  ifstream f("flip.in");
  ofstream g("flip.out");
  int i,j;

  f>>n>>m;
  for(i=1; i<=n; i++)
  {
	for(j=1; j<=m; j++)
	{
		f>>matrice[i][j];
	}
  }

  back(1);

  g<<sol;

  return 0;
}