#include<iostream>
using namespace std;

int main(){
	double a, b;
	
	while(1){
	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;
	}
	
}