发一波

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