spoj_cpp_clean/ACPC10A/ACPC10A-11.cpp

/*
 * Written by Nitin Kumar Maharana
 * nitin.maharana@gmail.com
 */

#include <iostream>

using namespace std;

int main(void)
{
	int a1, a2, a3;

	cin >> a1 >> a2 >> a3;

	while(a1 != 0 || a2 != 0 || a3 != 0)
	{
		if((a3 - a2) == (a2 - a1))
			cout << "AP " << (a3 + (a2-a1)) << endl;
		else
			cout << "GP " << (a3 * (a2/a1)) << endl;

		cin >> a1 >> a2 >> a3;		
	}

	return 0;
}