规则Rules：
填入1~7，使得每行、列、宫内数字不重复。任意两个呈马步的单元格中，不能有相同的数字。
Write 1~7, make numbers no repeated in each Row, column and Box. No two cells that is a knight-step away can contain the same digit.
◆无马数独规则 Rules of Anti Knight
◆在线做 Do it by CTC
◆在线做Do it by Penpa
