#include <bits/stdc++.h>

using namespace std;
int n,m,i,j,a[20][20],ans,st[40];
void  back(int vf)
{
    int i,x,y;
    for(i=-1;i<=1;i+=2)
    {
        st[vf] = i;
        if(vf==(n+m))
        {
            int sum = 0;
            for(x=1;x<=n;x++)
                for(y=1;y<=m;y++)
            {
                sum += a[x][y] * st[x] * st[n+y];
            }
            ans = max(ans , sum);
        }
        else back(vf+1);

    }
}
int main()
{
    ifstream fin("flip.in");
    ofstream fout("flip.out");
    fin >> n >> m;
    for(i=1;i<=n;i++)
        for(j=1;j<=m;j++)
            fin >> a[i][j];
    back(1);
    fout<<ans <<"\n";
    return 0;
}