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: Wrong Answer)

fun main(args: Array<String>) {
    val x = readLine()!!.split(" ").map { it.toLong() }
    var n = x[0]
    val k = x[1]
    val hikizan = Math.abs(n - k)
    var kaisuu = n / k
    val amari = n % k
    val amariDouble = amari.toDouble()
    val hannbun = k.toDouble() / 2
    if (amariDouble > hannbun){
        kaisuu = kaisuu + 1
        val a = kaisuu * hikizan
        n = n - a
        println(n)
    } else if (amari == 0.toLong()) {
        println(0)
    } else {
        val a = kaisuu * hikizan
        n = n - a
        println(n)
    }
}