#include<stdio.h>
#include<iostream>
using namespace std;
void TR(double x,double y,int K,int H)
{
int t;
double X;
X=x*100;t=(int)X;
if(t<3550)K=0;
else if(t<3550)K=0;
else if(t<3750)K=1;
else if(t<4000)K=2;
else if(t<4300)K=3;
else if(t<5000)K=4;
else if(t<5500)K=5;
else if(t<7000)K=6;
else if(t>=7000)K=7;

X=y*100;t=(int)X;
if(t<3550)K=0;
else if(t<7100)H=0;
else if(t<7700)H=1;
else if(t<8300)H=2;
else if(t<8900)H=3;
else if(t<10500)H=4;
else if(t<11600)H=5;
else if(t<14800)H=6;
else if(t>=14800)H=7;
}


}
int main(){
int K=0,H=0;
double x,y;
while(scanf("%lf %lf",&x,&y)!=EOF)
{K=0,H=0;

TR(x,y,K,H);
if(H<K)H=K;

switch(K){
case 0:
cout<<"AAA"<<endl;break;
case 1:
cout<<"AA"<<endl;break;
case 2:
cout<<"A"<<endl;break;
case 3:
cout<<"B"<<endl;break;
case 4:
cout<<"C"<<endl;break;
case 5:
cout<<"D"<<endl;break;
case 6:
cout<<"E"<<endl;break;
case 7:
cout<<"NA"<<endl;break;

}
}
return 0;
}