T = int(input())
for i in range(T):
    possible = True
    S = input()[::-1]
    course = []
    for j in range(len(S)):
        if S[j] == 'R':
            course.append('R')
        if S[j] == 'G':
            if 'R' in course:
                course[course.index('R')] = 'G'
            else:
                possible = False
        if S[j] == 'W':
            if 'G' in course:
                course[course.index('G')] = 'W'
            elif not 'W' in course:
                possible = False
    if possible:
        print('possible')
    else:
        print('impossible')