using System;
using System.Collections.Generic;
using System.Text;
using System.Linq;

class Program
{
    public void Proc()
    {
        Reader.IsDebug = false;
        int queryCount = int.Parse(Reader.ReadLine());
        StringBuilder ans = new StringBuilder();
        for(int i=0; i<queryCount; i++) {
            if(this.GetAns(Reader.ReadLine())) {
                ans.AppendLine("possible");
            } else {
                ans.AppendLine("impossible");
            }
        }
        Console.Write(ans.ToString());
    }

    private bool GetAns(String inpt) {
        int rCount = 0;
        int gCount = 0;
        int wCount = 0;

        for(int i=inpt.Length - 1; i>=0; i--) {
            if(inpt[i] == 'R') {
                rCount++;
            } else if(inpt[i] == 'G') {
                if(rCount == 0) {
                    return false;
                }
                rCount--;
                gCount++;
            } else {
                if(gCount == 0) {
                    if(wCount == 0) {
                        return false;
                    }
                } else {
                    gCount--;
                    wCount++;
                }
            }
        }
        if(rCount > 0 || gCount > 0) {
            return false;
        }
        return true;

    }


    public class Reader
    {
        public static bool IsDebug = true;
        private static String PlainInput = @"




 
";
        private static System.IO.StringReader Sr = null;
        public static string ReadLine()
        {
            if (IsDebug)
            {
                if (Sr == null)
                {
                    Sr = new System.IO.StringReader(PlainInput.Trim());
                }
                return Sr.ReadLine();
            }
            else
            {
                return Console.ReadLine();
            }
        }

    }
    static void Main()
    {
        Program prg = new Program();
        prg.Proc();
    }
}