Problem:
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.

Sample Input 1

7 4

Sample Output 1

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.

Sample Input 2

2 6

Sample Output 2

2

N=2 after zero operations is the minimum.

Sample Input 3

1000000000000000000 1

Sample Output 3

0

Solution in Scala (2.13.1) (judge verdict: Accepted)

import io.StdIn._
import scala.math.pow
 
object Main extends App {
  val arr = readLine.split(" ")
  val n   = arr(0).toLong
  val k   = arr(1).toLong
 
  require(0 <= n && n <= pow(10, 18))
  require(1 <= k && n <= pow(10, 18))
 
  val a = n % k
  val b = k - a
 
  if (a > b) println(b) else print(a)
}