tijie

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