def solve(s: str) -> bool:
    if s[-1] != 'R': return False

    w = 0
    g = 0
    r = 0
    for c in s:
        match c:
            case 'W':
                w += 1
            case 'G':
                if w == 0: return False
                w -= 1
                g += 1
            case 'R':
                if g == 0: return False
                g -= 1
                r += 1

    return True


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