def mrF(alg, times = 1):
    if times % 2 == 0:
        return alg
    elif alg == 'R':
        return "L'"
    elif alg[0] == 'G':
        return alg
    elif alg[-1] == "'":
        return alg[:-1]
    elif alg[-1] == '2':
        return alg
    else:
        return alg + "'"