#include<bits/stdc++.h> using namespace std; int main(){ int m; cin>>m; if(90<=m&&m<=100);cout<<"A"; if(80<=m&&m<90);cout<<"B"; if(70<=m&&m<80);cout<<"C"; if(60<=m&&m<70);cout<<"D"; if(m&&m<60);cout<<"E"; return 0; }