#include<iostream>
#include<cmath>
using namespace std;

int main(){
	int diem=0    ;
	cout <<"nhap diem trung binh: ";
	cin >>diem;
	if (diem >0 && diem < 5)
		cout <<"\nkhong dat";
	else if (diem >= 5 && diem < 6.5)
		cout <<"\ndat";
	else if (diem >= 6.5 && diem < 8)
		cout <<"\nkha";
	else if (diem >=8 && diem <=10)
		cout <<"\ngioi";
	else cout <<"\nban nhap sai";
	return 0;
}