12306 - 输出成绩的等级

#include<bits/stdc++.h>
using namespace std;
int main(){
	int n;
	cin>>n;
	if(n>=80) cout<<"A";
	else if(n>=70) cout<<"B";
	else if(n>=60) cout<<"C";
	else if(n>=50) cout<<"D";
	else cout<<"E";
	return 0;
}