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)

fun main(args: Array<String>) {
    val line1 = readLine()!!.trim()
    val (n: Long, k: Long) = line1.split(" ").map {it.toLong()}

    var cur: Long = n % k

    while (true) {
        val next = skill(cur, k)
        if (next > cur) {
            break
        }

        cur = next
    }

    println(cur)
}

fun skill(value: Long, value2: Long): Long {
    val result =  (value2 - value)
    if (result < 0) {
        return - result
    } else {
        return result
    }
}