for i in range(int(input())):
    cntw = cntg = cntr = 0
    possible = True
    for s in input():
        if s == 'W':
            cntw += 1
        if s == 'G':
            cntg += 1
        if s == 'R':
            cntr += 1

        if cntw < cntg or cntg < cntr:
            possible = False
    if cntg != cntr or (cntw != 0 and cntg == 0):
        possible = False
    if possible:
        print('possible')
    else:
        print('impossible')