#include <iostream>
using namespace std;

int main() {
int marks;
cin >> marks ;
if (marks>90){
	cout << "your grade is A";
}
 else if (marks > 80){
 	cout << "your grade is B ";
 }
 else if (marks < 70){
 	cout << "your grade is C";
 }
	return 0;
}