规则Rules：
标准数独基础上，提示数是这一方向上前若干个数字之和。X是这一方向上第一个数字。
Classic rules applied. Additionally, the clue is the first X numbers' sum, with X is the first number in this direction.
◆例题 Example
◆在线做Do it by CTC
◆在线做 Do it by Penpa
