#include <fstream>

using namespace std;

int main()
{
    ifstream f("flip.in");
    ofstream g("flip.out");
    int a,b,s=0;
    f>>a>>b;
    int v[a+1][b+1];
    for(int i=1; i<=a; i++)
        for(int j=1; j<=b; j++)
        {
            f>>v[i][j];

        }
         for(int i=1; i<=a; i++)
        for(int j=1; j<=b; j++)
            if(v[i][j]>0) s=s+v[i][j];

        g<<s;
    return 0;
}