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

int main(void)
{
    int n, m, temp;
    int sum = 0;
    ifstream f("flip.in");
    ofstream g("flip.out");

    f >> n >> m;
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < m; j++)
        {
            f >> temp;
            if (temp > 0)
                sum += temp;
        }
    }
    g << sum;
    return 0;
}