сами то подумайте и изучите https://www.google.com/search?q=%D0%B1%D0%B5%D1%81%D1%87%D0%B8%D0%BD%D1%81%D1%82%D0%B2%D0%B0+%D0%B0%D1%81%D0%B0%D0%B4%D0%B0&ie=utf-8&oe=utf-8