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

int main() {
	ifstream fin("flip.in");
	ofstream fout;
	int i, j, a[100][100], n, m, sum=0;
	fin >> n >> m;
	for (i = 1; i <= n; i++)
		for (j = 1; j <= m; j++)
		{
			fin >> a[i][j];
			if (a[i][j] > 0)
				sum+=a[i][j];
		}
	fout.open("flip.out");
	fout << sum;
	fout.close();
	


}