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

int a[101][101];

int main()
{
    int i, j, n ,m, sum = 0;
    ifstream fin("flip.in");
    fin>>n;
    fin>>m;
    for(i=0; i<n;i++)
        for(j=0;j<m;j++)
        {
            fin>>a[i][j];
            if(a[i][j] > 0)
                sum += a[i][j];
        }
    fin.close();

    ofstream fout("flip.out");
    fout<<sum;
    fout.close();
    return 0;
}