#include <bits/stdc++.h>
using namespace std;
int main()
{
  /*
  florr 名字叫oww
  lvl 89
  full mythic
  */
  long long a, b, c;
  while(scanf("%lld%lld%lld", &a, &b, &c) != EOF)
  {
    if(a == 0 && b == 0 && c == 0)
    {
        return 0;
    }
    if(b - a == c - b)
    {
      printf("AP %lld\n", 2 * c - b);
    }
    else
    {
      printf("GP %lld\n", c * c / b);
  	}
  }
  return 0;
}

为什么会显示未知错误