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 (1.3.71) (judge verdict: Accepted)

import java.lang.Long.min
import java.lang.Math.abs


fun main (args:Array<String>) {
    var (N, K) = readLine()!!.split(" ").map(String::toLong)
    var minResult = N
    if (N > K) {
        N = N % K
        minResult = N
    }
    while (true) {
        N = abs(N - K)
        if (minResult == N) {
            break
        }
        minResult = min(N, minResult)
    }
    print(minResult)
}