#include <fstream>
using namespace std;

ifstream cin ("flip.in");
ofstream cout ("flip.out");

int main() {

    int N, M;
    cin >> N >> M;
    int A[16][16];
    int S = 0;
    for (int i = 1; i <= N; ++i)
        for (int j = 1; j <= M; ++j)
            cin >> A[i][j];
    for (int i = 1; i <= N; ++i) {
        for (int j = 1; j <= M; ++j) {
            if (j == 2 || i == 3)
                S += A[i][j] * (-1);
            else
                S += A[i][j];
        }
    }
    cout << S;
    cin.close();
    cout.close();
    return 0;

}