Minimum Extra Chocolates

Add a non-negative number of chocolates to each of the two boxes so that Drake's total becomes a positive integer multiple of Alex's total, and find the minimum total added. This site makes k≥1, X,Y≥0 and the ranges explicit.

输入格式

One line with two positive integers A and B (1≤A,B≤10^9).

输出格式

Output the minimum non-negative integer X+Y such that some positive integer k satisfies k(A+X)=B+Y.

样例 1

输入：

8 16

输出：

0

样例 2

输入：

7 37

输出：

4

样例 3

输入：

70 229

输出：

9