规则Rules：
标准数独基础上，每条箭头上的数字之和，等于圆圈里的一位或两位数。两位数的阅读方式是从左到右、从上到下。
Classic rules applied. Additionally, the sum of numbers on each line equals to the numbers, or the 2-digit numbers in circle. The 2-digit number should be read from left to right, up to down.
