#include <iostream>
#include <fstream>
using namespace std;
long int smax,a[17][17],semnl[17],semnc[17];
int n,m;
void calcul_sum()
{int i,j;
long sum=0;
for(i=1;i<=n;i++)
 for(j=1;j<=m;j++)
    sum+=semnl[i]*semnc[j]*a[i][j];
   if(sum>smax)smax=sum;
}

void gencol(int k)
{if(k==m+1)
  calcul_sum();
 else{
  semnc[k]=-1;
  gencol(k+1);
  semnc[k]=1;
  gencol(k+1);
    }
}

void genlin(int k)
{if(k==n+1)
  gencol(1);
 else{
  semnl[k]=-1;
  genlin(k+1);
  semnl[k]=1;
  genlin(k+1);
    }
}

int main()
{int i,j;
ifstream f("flip.in");
ofstream g("flip.out");
f>>n>>m;
for(i=1;i<=n;i++)
     for(j=1;j<=m;j++)
     f>>a[i][j];
genlin(1);
g<<smax;
}