#include <fstream>
#include <stdio.h>
#define maxim 16

using namespace std;

long long v[maxim][maxim];
char lin[maxim+1];
char col[maxim+1];

void inc_lin ( int l ) {
  int i = 0;
  while ( i < l && lin[i] == 1 ) {
    lin[i] = 0;
    i++;
  }

  if ( i < l ) {
    lin[i] = 1;
  }
}

long long _max ( long long a, long long b ) {
  if ( a > b )
    return a;
  else
    return b;
}

int main () {
  ifstream fin ( "flip.in" );
  ofstream fout ( "flip.out" );

  int l, c;

  fin>>l>>c;

  int i, j;

  for ( i = 0; i < l; i++ )
    for ( j = 0; j < c; j++ )
      fin>>v[i][j];

  long long s = 0LL, smax = -1000000LL;
  int cs, k;

  for ( i = 0; i < 1<<l; i++ ) {
    s = 0LL;
    for ( j = 0; j < c; j++ ) {
      cs = 0;
      for ( k = 0; k < l; k++ ) {
        if ( lin[k] == 0 )
          cs += v[k][j];
        else
          cs -= v[k][j];
      }

      if ( cs < 0 ) {
        col[j] = 1;
        s -= cs;
      }
      else {
        col[j] = 0;
        s += cs;
      }
    }

    smax = _max ( smax, s );
    inc_lin ( l );
  }

  fout<<smax<<'\n';

  fin.close ();
  fout.close ();

  return 0;
}