#include<bits/stdc++.h> using namespace std; int main(){ int a; cin>>a; if(a>90)cout<<"A"<<endl; else if(a>=80&&a<90)cout<<"B"<endl; else if(a>=70a<80)cout<<"C"<<endl; else if(a>=60a<70)cout<<"D"<<endl; else cout<<"E"<<endl; return 0; }