#include <iostream>
using namespace std;

int main()
{
	double a,b;
	while(cin >> a >> b)
	{
		     if(a<35.50 && b< 71.00) cout << "AAA";
		else if(a<37.50 && b< 77.00) cout << "AA";
		else if(a<40.00 && b< 83.00) cout << "A";
		else if(a<43.00 && b< 89.00) cout << "B";
		else if(a<50.00 && b<105.00) cout << "C";
		else if(a<55.00 && b<116.00) cout << "D";
		else if(a<70.00 && b<148.00) cout << "E";
		else						 cout << "NA";
		cout << endl;
	}
}