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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.Scanner;

// https://atcoder.jp/contests/abc161/tasks/abc161_c
public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ

		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
		long k = sc.nextLong();
		sc.close();

		long[] ansArray =  {n,n,n};

		n = n%k;
		long ans = n;
		long ans1 = n;
		long ans2 = n;
		while(true) {
			ansArray[2] = Math.abs(ansArray[1] - k);

			ans = Math.abs(ans - k);
			ans1 = Math.abs(ans - k);
			ans2 = Math.abs(ans1 - k);

			if(ans==ans2) {
				System.out.println(Math.min(ans1, ans2));
				return;
			}
		}


	}
}