#include<iostream> using namespace std; int main(){ int s; cin>>s; if(s>=90) cout<<"A"<<endl; else if(s<90&&s>=80) cout<<"B"<<endl; else if(s<80&&s>=70) cout<<"C"<<endl; else if(s<70&&s>=60) cout<<"D"<<endl; else cout<<"E"<<endl; return 0; }