def main():
    from math import sqrt,sin,cos,tan,ceil,radians,floor,gcd,exp,log,log10,log2,factorial,fsum
    from heapq import heapify, heappop, heappush
    from bisect import bisect_left, bisect_right
    from copy import deepcopy
    import copy
    import random
    from collections import deque,Counter,defaultdict
    from itertools import permutations,combinations
    from decimal import Decimal,ROUND_HALF_UP
    #tmp = Decimal(mid).quantize(Decimal('0'), rounding=ROUND_HALF_UP)
    from functools import lru_cache, reduce
    #@lru_cache(maxsize=None)
    from operator import add,sub,mul,xor,and_,or_,itemgetter
    INF = 10**18
    mod1 = 10**9+7
    mod2 = 998244353
    
    #DecimalならPython
    #再帰ならPython!!!!!!!!!!!!!!!!!!!!!!!!!!
    
    
    '''
    何をチェックすべきか
    まず、赤と緑の数が一致してるか
    緑赤の順番できているか
    
    
    '''
    
    for _ in range(int(input())):
        S = list(input())
        N = len(S)
        r = 0
        g = 0
        for i in range(N):
            if S[i] == 'G':
                g += 1
            elif S[i] == 'R':
                r += 1
                if r > g:
                    print('impossible')
                    break
        else:
            if r != g:
                print('impossible')
            elif S[-1] == 'W':
                print('impossible')
            else:
                print('possible')
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
if __name__ == '__main__':
    main()