#include <bits/stdc++.h> using namespace std; int main() { int a; cin>>a; if(a>=90) cout<<"A"<<endl; else if(a>=80&&a<=89) cout<<"B"<<endl; else if(a>=70&&a<=79) cout<<"C"<<endl; else if(a>=60&&a<=69) cout<<"D"<<endl; else if(a<60) cout<<"E"<<endl; }