T = int(input())

for _ in range(T):
    S = input()
    W_cnt, G_cnt, R_cnt = 0, 0, 0
    
    for S_i in S:
        if S_i == 'W':
            W_cnt += 1
        if S_i == 'G':
            G_cnt += 1
        if S_i == 'R':
            R_cnt += 1
    
        if W_cnt < G_cnt or G_cnt < R_cnt:
            print('impossible')
            break
    else:
        if G_cnt == R_cnt:
            print('possible')
        else:
            print('impossible')