题解

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