规则Rules：
标准数独基础上，每条线条上的数字之和等于圆圈里的数字。
Classic rules applied. Additionally, the sum of numbers on each line is the numbers in circle.
◆例题 Example
◆在线涂鸦 Draw it Online
◆在线做 Do it by CTC
◆在线做 Do it by Penpa
