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: Runtime Error)

import java.util.*;
import java.math.RoundingMode;
import java.math.BigDecimal;

public class Main{
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		Long n = sc.nextLong();
		Long k = sc.nextLong();
		Long min = Math.min(n, k);
		Long max = Math.max(n, k);
		Long mod = max%min;
		if(min == 1 || n==k) {
			System.out.println(0);
		}
		else {
			Long ans = Math.abs(mod-min);
			System.out.println(ans);
		}
	}
}