#include<fstream.h>
int n,m,a[16][16],nn[34]={0};
long max=0;
ifstream in("flip.in");
ofstream out("flip.out");

void check()
{int sum=0;
 for(int i=1;i<=n;i++)
 {
  for(int j=1;j<=m;j++)
  {
   sum=sum+a[n][m]*nn[i]*nn[n+j];
  }
 }
 if(sum>max)max=sum;
}

void back(int i)
{
  for(int k=1;k<=-1;k=k-2)
  {
    nn[i]=k;
    if(i==n+m)check();
    else back(i+1);
  }
}

int main()
{

 //citire
 in>>n>>m;
 for(int i=1;i<=n;i++)
  for(int j=1;j<=m;j++)
   in>>a[n][m];
 //Back
 back(1);
 out<<max;
}