#include <iostream>
#include <math.h>
#include <fstream>
#include <limits.h>

using namespace std;

int main()
{
    ifstream f("flip.in");
    ofstream g("flip.out");
    int v[100][100],i,j,n,m,s=0;
    f>>n>>m;
    for(i=1;i<=n;++i)
    for(j=1;j<=m;++j)
    f>>v[i][j];
    for(i=1;i<=n;++i)
    for(j=1;j<=m;++j)
    if(v[i][j]>0)
    s+=v[i][j];
    g<<s<<endl;


    f.close();
    g.close();
    return 0;
}