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

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

int main() {
    int n, m, sum = 0;
    fin >> n >> m;
    for(int i = 1;i <= n; i++)  {
        for(int j = 1; j <= m; j++) {
            int x;
            fin >> x;
            if(x > 0) sum += x;
        }
    }
    fout << sum;
}