#include <iostream>
#include <fstream>

using namespace std;

ifstream fin ("flip.in");
ofstream fout ("flip.out");

int main()
{
    int s = 0, m, n, a[100][100];
    fin >> n >> m;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++)
        {
            fin >> a[i][j];
        }
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++)
        {
            if (a[i][j] > 0) s = s + a[i][j];
        }
    fout << s;
    return 0;
}