#!/usr/bin/env python

num = int(raw_input())
for i in range(num):
    str = raw_input()
    show = list(str)
    red = 0
    green = 0
    white = 0
    length = len(str)
    for j in range(length):
        if show[length - 1 - j] == "R":
            red += 1
        elif show[length - 1 - j] == "G":
            green += 1
        else:
            white += 1

        if red < green:
            break
    if red ==  green and white >= red:
        print("possible")
    else:
        print("impossible")