#include<fstream>

using namespace std;

int main()
{
	int a,b,m[17][17],i,j,s=0;
	ifstream fin("flip.in");
	ofstream fout("flip.out");
	fin>>a>>b;
	for(i=1;i<=a;++i)
		for(j=1;j<=b;++j){
			fin>>m[i][j];
		if(m[i][j]>0){
			s=s+m[i][j];
		}
		}
		fout<<s;
		return 0;
}