def check(str):
    if str.count('R') != str.count('G'):
        return 'impossible'
    elif str.count('W') < str.count('R'):
        return 'impossible'
    lines = [0] * str.count('R')
    for s in str:
        if s == 'W':
            if 0 not in lines:
                return 'impossible'
        elif s == 'G':
            try:
                lines[lines.index(0)] = 1
            except:
                return 'impossible'
        elif s == 'R':
            try:
                lines[lines.index(1)] = 2
            except:
                return 'impossible'

    return 'possible'

T = input()
for t in range(T):
    print check(raw_input())