#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("flip.in");
ofstream fout("flip.out");
int suma, n, m, a[20][20];
int main()
{
    fin>>n>>m;
    for (int i=1; i<=n; i++)
    {
        for (int j=1; j<=m; j++) {fin>>a[i][j]; suma+=a[i][j];}
    }
    for (int i=1; i<=n; i++)
    {
        int s=0;
        for (int j=1; j<=m; j++) s+=a[i][j];
        if (s<0) suma-=2*s;
    }
    for (int i=1; i<=m; i++)
    {
        int s=0;
        for (int j=1; j<=n; j++)
        {
            s+=a[j][i];
        }
        if (s<0) suma-=2*s;
    }
    fout<<suma;
}