#include <iostream>
#include <fstream>

using namespace std;

ifstream in ("flip.in");
ofstream out ("flip.out");
int main()
{
    int V[16][16],n,m,afisare=0;
    in >> n >> m;
    for(int i = 0; i<n;i++){
        for(int j = 0; j<m;j++){
            in >> V[i][j];
            if(V[i][j] > 0){
                afisare += V[i][j];
            }
        }
    }
    out << afisare;
    return 0;
}