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