#include <stdio.h>
#include <iostream>
#define MAX 16

using namespace std;
int A[MAX][MAX], L[MAX], C[MAX], Lv[MAX], Cv[MAX], Max;
int total(int n, int m)
{
  int suma, i, j;

  suma = 0;
  for(i = 0; i < n; i++)suma += L[i];
  for(i = 0; i < n; i++)
    for(j = 0; j < m; j++)if(Lv[i] == 1 && Cv[j] == 1)suma += 2 * A[i][j];
  return suma;
}
void bkt(int n, int m, int k)
{
  int suma;

  if(k == n)
  {
    suma = total(n, m);
    if(Max < suma)Max = suma;

  }
  else
  {
    L[k] *= -1;
    Lv[k] = 1;
    bkt(n, m, k + 1);
    L[k] *= -1;
    Lv[k] = 0;
    bkt(n, m, k + 1);
  }
}
int main()
{
  FILE *fin, *fout;
  int n, m, i, j;

  fin = fopen("flip.in", "r");
  fout = fopen("flip.out", "w");
  fscanf(fin, "%d%d", &n, &m);
  for(i = 0; i < n; i++)
    for(j = 0; j < m; j++)
    {
      fscanf(fin, "%d", &A[i][j]);
      C[j] += A[i][j];
    }
  for(i = 0; i < m; i++)
    if(C[i] < 0)
    {
      for(j = 0; j < n; j++)A[j][i] *= -1;
      Cv[i] = 1;
    }
  for(i = 0; i < n; i++)
    for(j = 0; j < m; j++)
      L[i] += A[i][j];
  bkt(n, m, 0);
  fprintf(fout, "%d", Max);
  fclose( fin );
  fclose( fout );
  return 0;
}