Учитесь: https://ru.m.wikipedia.org/wiki/%D0%A1%D1%83%D0%B4%D0%B5%D0%B1%D0%BD%D0%B0%D1%8F_%D1%81%D0%B8%D1%81%D1%82%D0%B5%D0%BC%D0%B0_%D0%A0%D0%BE%D1%81%D1%81%D0%B8%D0%B8