#include<iostream>

using namespace std;

int main(){

	double a,b;

	while(cin>>a>>b){
		if(a<35.50&&b<71.0) cout<<"AAA"<<endl;
		else if(a<37.50&&b<77.0) cout<<"AA"<<endl;
		else if(a<40.0&&b<83.0) cout<<"A"<<endl;
		else if(a<43.0&&b<89.0) cout<<"B"<<endl;
		else if(a<50.0&&b<105.0) cout<<"C"<<endl;
		else if(a<55.0&&b<116.0) cout<<"D"<<endl;
		else if(a<70.0&&b<148.0) cout<<"E"<<endl;
		else cout<<"NA"<<endl;
	}

}