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 Kotlin (1.0.0) (judge verdict: Accepted)

import java.io.PrintWriter
import java.util.*

val pw = PrintWriter(System.out)
val sc = Scanner(System.`in`)

fun main(args: Array<String>) {
    val n = sc.nextLong()
    val k = sc.nextLong()
    abc161c(n,k)
}

fun abc161c(n:Long, k:Long) {
   if(n == k){
       println(0)
   }else if(n > k){
       val tmp = n % k
       val next = Math.abs(tmp-k)
       if(tmp > next) println(next) else println(tmp)
   }else{
       if(Math.abs(n-k) > n) println(n) else println(Math.abs(n-k))
   }
}

fun next() = readLine()!!
fun nextInt() = next().toInt()
fun nextLong() = next().toLong()
fun nextDouble() = next().toDouble()
fun nextListOfString() = next().split(" ")
fun nextListOfInt() = nextListOfString().map { it.toInt() }
fun nextListOfLong() = nextListOfString().map { it.toLong() }
fun nextListOfDouble() = nextListOfString().map { it.toDouble() }