include<bits/stdc++.h>

using namespace std ;

int main(){

char grade;

cin>>grade;

switch(grade)

{

case'A': cout<<"Very good!\n";break;

case'B': cout<<"Good!\n";break;

case'C': cout<<"OK!\n";break;

case'D': cout<<"Bad!\n";break;

default: cout<<"Too bad!\n";

}

return 0;

}