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() {
    val input = rsplong()
    val x = input[0]
    val k = input[1]
    val min = when {
        x <= k / 2 -> x
        x < k -> k - x
        x % k > k / 2 -> k - x % k
        else -> x % k
    }
    println(min)
}

fun rl() = readLine()!!
fun rsp() = readLine()!!.split(" ")
fun rint() = readLine()!!.toInt()
fun rspint() = readLine()!!.split(" ").map(String::toInt)
fun rsplong() = readLine()!!.split(" ").map(String::toLong)

fun main(args: Array<String>) = main()