def solve(S):
    r, g, w, = 0, 0, 0
    for s in S[::-1]:
        if s == 'R':
            r += 1
        elif s == 'G':
            g += 1
            if g > r:
                return False
        elif g == 0:
            return False
        elif w < g:
            w += 1
    return w == g == r


T = int(input())
for t in range(T):
    S = input().strip()
    if solve(S):
        print('possible')
    else:
        print('impossible')