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: Wrong Answer)

import java.util.*; 
import java.lang.*; 

public class Main{
	public static void main(String[] args){
		Scanner scan = new Scanner(System.in);
		
		long N = scan.nextLong();
		long K = scan.nextLong();
		
		if(N>=K){
		if(N%K==0){
			System.out.println(0);
		}
		else{
			if((N/2.0) >= N%K){
			N = N-(K*((N/K)+1))+N%K-1;
			System.out.println(N);
			if(N<=0){
				N=N*(-1);
			}
			}
			
			else{
			N = N-(K*(N/K))-N%K+1;
			
			if(N<=0){
				N=N*(-1);
			}
			System.out.println(N);
			}
		}
		}
		
		else{
			if(K>=N*2){
				System.out.println(N);
			}
			
			else{
				System.out.println(K-N);
			}
		}
	}
}