#include <iostream> //designed by hu 2025-10 using namespace std; int main(){ int g; cin>>g; if( g>=90 ){ cout << "A"; } else if( g>=80 ){ cout << "B"; } else if( g>=70 ){ cout << "C"; } else if( g>=60 ){ cout << "D"; } else{ cout << "E"; } return 0; }