dic = {"G": 0, "R": 1, "W": 2}
for _ in range(int(input())):
    S = input()
    X = [0, 0]
    for s in S:
        if dic[s] < 2:
            X[dic[s]] += 1
            if X[1] > X[0]:
                print("impossible")
                break
    else:
        if X[0] == X[1]:
            print("possible")
        else:
            print("impossible")