题解

#include<bits/stdc++.h>
#define ll long long                                                                  //防抄袭标记
#define MAXN 100005
#define maxn 1000005
#define MAXM 10000005
#define maxm 100000005
using namespace std;
int n;
int main(){
	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;
}