import sys
def I(): return int(sys.stdin.readline().rstrip())
def S(): return sys.stdin.readline().rstrip()


T = I()
for _ in range(T):
    U = S()[::-1]
    r,g,w = 0,0,0
    for u in U:
        if u == 'R':
            r += 1
        elif u == 'G':
            g += 1
        else:
            w += 1
        if r < g:
            print('impossible')
            break
    else:
        if r != g:
            print('impossible')
        else:
            print('possible')