using System;
using System.Collections;
using System.Collections.Generic;
 
class TEST{
	static void Main(){
		Sol mySol =new Sol();
		mySol.Solve();
	}
}

class Sol{
	public void Solve(){
		for(;T>0;T--){
			String S=rs();
			int r=0;
			int g=0;
			int w=0;
			bool chk=true;
			bool wok=false;
			for(int i=S.Length-1;i>=0;i--){
				if(S[i]=='R'){
					r++;
					
					continue;
				}
				if(S[i]=='W'){
					if(r==0){chk=false;break;}
					if(g==0){chk=false;break;}
					if(!wok){chk=false;break;}
					w++;
					continue;
				}
				if(S[i]=='G'){
					g++;
					if(r>0)wok=true;
					if(g>r){chk=false;break;}
					continue;
				}
			}
			Console.WriteLine( (chk&(r==g)&(r+g+w>=3)&(w>=r))?"possible":"impossible");
		
		}
	}
	int T;
	public Sol(){
		T=ri();
	}




	static String rs(){return Console.ReadLine();}
	static int ri(){return int.Parse(Console.ReadLine());}
	static long rl(){return long.Parse(Console.ReadLine());}
	static double rd(){return double.Parse(Console.ReadLine());}
	static String[] rsa(){return Console.ReadLine().Split(' ');}
	static int[] ria(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>int.Parse(e));}
	static long[] rla(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>long.Parse(e));}
	static double[] rda(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>double.Parse(e));}
}