#include<bits/stdc++.h>
using namespace std;
int main(){
	int a;
	scanf("%d",&a);
	if(a>=86){
		cout<<"VERY GOOD"<<endl;	
	}
	if(a>=85,a<=60){
		cout<<"GOOD"<<endl;	
	}
 	if(a<60){
		cout<<"ABD";	
	}
}
/**************************************************************
	Problem: 1035
	User: toughuatao1
	Language: C++
	Result: Wrong Answer
****************************************************************/