#include <iostream>
using namespace std;
/* run this program using the console pauser or add your own getch, system("pause") or input loop */

int main(int argc, char** argv) {
	//目的：while重複判斷分數等級
	int s1=0 ;
	while(s1 != -1){
		cout<<"\nplease input your score = (press -1 to exit)";		
		cin>>s1;		
		
		int grade = s1/10;	
		switch(grade){
			case 10:
				cout<<"score "<<s1<<", grade = A++"<<endl;
				break; 
			case 9:
				cout<<"score "<<s1<<", grade = A"<<endl;
				break;			
			case 8:
				cout<<"score "<<s1<<", grade = B"<<endl;
				break;			
			case 7:
				cout<<"score "<<s1<<", grade = C"<<endl;
				break;			
			case 6:
				cout<<"score "<<s1<<", grade = D"<<endl;
				break;			
			case 5:
				cout<<"score "<<s1<<", grade = E"<<endl;
				break;			
			default:
				cout<<"score "<<s1<<", grade = F"<<endl;
				break;						
		}
	}
	
	
	return 0;
}