规则Rules：
填入1~6，使得每行、列、宫内数字不重复，宫可能是不规则的。白色格内不填入数字。
Write 1~6, make numbers no repeated in each Row, Column and Boxes. The Box may be irregular, and you don't need to fill the white cells.
◆在线涂鸦 Draw it Online
◆在线做 Do it by CTC
◆在线做 Do it by Penpa
