C - Replacing Integer

Score : $300$ points

Problem Statement

Given any integer $x$, Aoki can do the operation below.

Operation: Replace $x$ with the absolute difference of $x$ and $K$.

You are given the initial value of an integer $N$. Find the minimum possible value taken by $N$ after Aoki does the operation zero or more times.

Constraints

• $0 ≤ N ≤ 10^{18}$
• $1 ≤ K ≤ 10^{18}$
• All values in input are integers.

Input

Input is given from Standard Input in the following format:

$N$ $K$

Output

Print the minimum possible value taken by $N$ after Aoki does the operation zero or more times.

7 4

1

Initially, $N=7$.

After one operation, $N$ becomes $|7-4| = 3$.

After two operations, $N$ becomes $|3-4| = 1$, which is the minimum value taken by $N$.

2 6

2

$N=2$ after zero operations is the minimum.

1000000000000000000 1

0