#include<bits/stdc++.h> using namespace std; int main(){ int a; cin>>a; if(a>100){ cout<<"错误，请重新输入成绩"; } else if(a>=90){ cout<<"A"; } else if(a>=80){ cout<<"B"; } else if(a>=70){ cout<<"C"; } else if(a>=60){ cout<<"D"; } else if(a<60){ cout<<"E"; } }