#include<stdio.h>
int main() {
	int a,b,c;
	scanf("%d%d%d",&a,&b,&c);
	while(a!=0 || b!=0 || c!=0)
	{
	if(a>=b && a-b==b-c) //Decreasing AP
	{
	printf("AP ");
	printf("%d\n",c+(a-b));
	}
	if (a<b && b-a==c-b) //Increasing AP
	{
	printf("AP ");
	printf("%d\n",c+(b-a));
	}	
	else
	{
		int r;
	    if(a>b)
	    {
		    if(b!=0) r=a/b;
	    	else if(c!=0)
	    	r=b/c;
	    	printf("GP ");
	    	printf("%d\n",c/(r));
	    }
		 else if(a<b)
		 {
		 	if(a!=0)
			r=b/a;
			else if(b!=0)
			r=c/b;
			printf("GP ");
			printf("%d\n",a*(r*r*r));
		 }
	}
	scanf("%lld%lld%lld",&a,&b,&c);
	}
	return 0;
}

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MiAtNCA4CjIgNiAxOAowIDAgMAo=

2 -4 8
2 6 18
0 0 0