#include <iostream>
#include <fstream>


using namespace std;

int n, m;
long int a[16][16];

long int mx = -16000000;

int lc[32];

long int calcSum()
{
    long int s = 0;
    for(int i = 0; i < n; i++)
        for(int j = 0; j < m; j++)
            s+=a[i][j] * lc[i] * lc[i+j+1];
    return s;
}
int factorial(int n)
{
  return (n == 1 || n == 0) ? 1 : factorial(n - 1) * n;
}

void permute(int* v, int l)
{
    int i = l-1;
    int step = 0;
    do{
        if(v[i] == -1)
        {
            v[i] = 1;
            i = l-1;
            step++;

            mx = max(mx, calcSum());

        }
        else
        if(v[i] == 1)
        {
            v[i] = -1;
            i--;
        }
    }while(step < l*l);
}

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

    f >> n >> m;
    for(int i = 0; i < n; i++)
        for(int j = 0; j < m; j++)
            f >> a[i][j];

    for(int i = 0; i < m+n; i++)
        lc[i] = -1;

    permute(lc, m+n);


    g << mx;


    return 0;
}