#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("flip.in");
ofstream fout("flip.out");
int n,m,x,f[35],v[17][17],i,j,k,s,mx;
int main()
{
    fin>>n>>m;
    for (i=1;i<=n;i++)
        for (j=1;j<=m;j++)
        {
            fin>>v[i][j];
        }
    mx=-2e7;
    for (i=1;i<=(1<<(n+m))-1;i++)
    {
         j=0;
        while (f[++j]!=0) f[j]=0;
        f[j]=1;
        s=0;
        for (j=1;j<=n;j++)
            for (k=1;k<=m;k++)
        {
            if (f[j]+f[n+k]==1) s-=v[j][k];
                else s+=v[j][k];
        }
        if (s>mx) mx=s;
    }
    fout<<mx;
    return 0;
}