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