import fol

if __name__ == '__main__':
    kb = fol.kb.Kb()
    try:
        kb.tell('Friend(ALICE, BOB)')
        kb.tell('Friend(BOB, CLAIRE)')
        kb.tell('Friend(x, y) -> Friend(y, x)')
        kb.tell('(Friend(x, y) & Friend(y, z)) -> Friend(x, z)')

        print(kb.ask('Friend(ALICE, x)'))
    except KeyboardInterrupt:
        pass