#include<bits/stdc++.h> using namespace std; int main() { // 1 3 5 "NO " "yes" int a; cin>>a;//99 90 98 a= a/10; switch(a){ // 90 91 92 93 94 95 十位10 9 8 7 6 6以下 case 10: case 9:cout<<"A";break; case 8: case 7:cout<<"B";break; case 6 : cout<<"C"; break; default:cout<<"D"; } return 0; }