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 Java (OpenJDK 11.0.6) (judge verdict: Wrong Answer)

import java.util.Scanner;

public class Main {
	
	   

		public static void main(String[] args) {
	        Scanner sc = new Scanner(System.in);
	        Long n = sc.nextLong();
	        Long k = sc.nextLong();
//	        int z = sc.nextInt();
	        Long result = n;
	        boolean smaller = true;
	        if(k==1) {
	        	result = 0l;
	        }else if(n % k == 0) {
	        	result =0l;
	        }
	        else {
	        while(smaller) {
	        n = Math.abs(n-k);
	        //Long temp = n;
	        result = Math.min(n, result);
	        if(result == Math.abs(Math.abs(result-k)-k)) {
	        	result = Math.abs(result-k);
	        	//smaller = false;
	        	break;
	        }
	        }
	       
	        }
	        System.out.println(result);
	        
            //System.out.println(res); 
	        
	}
}