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

int main(){
	double inp1,inp2;
	while(cin >> inp1 >> inp2){
		string opt="NA";
		if(inp1<35.5 && inp2<71.0){
			opt = "AAA";
		}else if(inp1<37.5 && inp2<77.0){
			opt = "AA";
		}else if(inp1<40.0 && inp2<83.0){
			opt = "A";
		}else if(inp1<43.0 && inp2<89.0){
			opt = "B";
		}else if(inp1<50.0 && inp2<105.0){
			opt = "C";
		}else if(inp1<55.0 && inp2<116.0){
			opt = "D";
		}else if(inp1<70.0 && inp2<148.0){
			opt = "E";
		}
		cout << opt << endl;
	}
	return 0;
}