~cpp
#include <iostream>
using namespace std;
int main(){
int jumsu;
int grade[5]={0,};
char g='A';
do{
cin >> jumsu;
if(jumsu == 999) continue;
else if(jumsu > 100 || jumsu < 0) continue;
switch(jumsu/10){
case 10:
++grade[0]; break;
case 9:
++grade[0]; break;
case 8:
++grade[1]; break;
case 7:
++grade[2]; break;
case 6:
++grade[3]; break;
default:
++grade[4]; break;
}
}while(jumsu != 999);
for(int i = 0; i < 4; i++){
cout << (char)(g+i)<< " : " <<grade[i]<<" 명"<<endl;
}
cout << "F : " <<grade[4]<<" 명"<<endl;
return 0;
}