#include <iostream>
#include <fstream>
using namespace std;
ifstream f("flip.in");
ofstream g("flip.out");
int main()
{
    int a,b,v[100][100],i,j,s=0;
    f>>a>>b;
    for(i=1;i<=a;i++)
        for(j=1;j<=b;j++)
        f>>v[i][j];
    for(i=1;i<=a;i++)
    for(j=1;j<=b;j++)
    if(v[i][j]>0)
        s=s+v[i][j];
    g<<s;


    return 0;
}