#include <iostream>

using namespace std;

int main()
{
	float x;
	char status;

	cout << "Input x: ";
	cin >> x;

	if ((x >= 3) && (x <= 8))
		status = 'A';
	else if ((x <= 0) || (x >= 10))
		status = 'B';
	else
		status = 'C';
	
	cout << status << endl;

	return 0;
}