题解

#include<iostream>
using namespace std;
int main(){
int n;
cin>>n;
if(n>=90 and n<=100) cout<<'A';
if(n>=80 and n<=89 ) cout<<'B';
if(n>=70 and n<=79 ) cout<<'C';
if(n>=60 and n<=69 ) cout<<'D';
if(n>=0 and n<=59 ) cout<<'E';
return 0;
}