#include <iostream>
#include <fstream>
using namespace std;

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

    int n, m, a[50][50];
    in >> n >> m;

    int sfinal = 0, s = 0;
    for(int i = 0; i < n; i++)
        for(int j = 0; j <= m; j++)
            in >> a[i][j];

    for(int i = 0; i < n; i++) {
        for(int j = 0; j <= m; j++)
            s = s + a[i][j];
        if(s >= 0)
            sfinal += s;
        else
            sfinal -= s;
        s = 0;
    }
    for(int j = 0; i < n; i++) {
        for(int i = 0; j <= m; j++)
            s = s + a[i][j];
        if(s >= 0)
            sfinal += s;
        else
            sfinal -= s;
        s = 0;
    }
    out << sfinal;
}