using System;
using System.Linq;

class Program
{
    static void Main()
    {
        int t = int.Parse(Console.ReadLine());

        for (int i=0;i< t; i++)
        {
            int g = 0, r = 0;
            string s = Console.ReadLine();
            int cnt = s.Length - s.Remove('G').Length;
            for (int j=0; j < s.Length; j++)
            {
                if (s[j] == 'G') g++;
                if (s[j] == 'R') r++;
                if (g == cnt && s[j] == 'W')
                {
                    Console.WriteLine("impossible");
                    break;
                }
                if (r > g)
                {
                    Console.WriteLine("impossible");
                    break;
                }
                if (j == s.Length - 1)
                {
                    if (r == g)
                    {
                        if (!(s[j] == 'R')) Console.WriteLine("impossible");
                        else Console.WriteLine("possible");
                    }
                    else Console.WriteLine("impossible");
                }
            }
        }
    }
}