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: Time Limit Exceeded)

import java.util.Scanner;
import java.lang.Math;
public class Main{
  public static void main(String[] args){
    Scanner a = new Scanner(System.in);
    long k = a.nextLong();
    long n = a.nextLong();
    while(k>=0){
        if(k == 0){
            System.out.print(k);
            break;
        }
        if(n == 1){
            System.out.print(0);
            break;
        }
        if(k%n == 0){
            System.out.print(0);
            break;
        }
        
        if(k < n ){
            System.out.print(Math.min(k, Math.abs(k-n)));
        }
        k -= n;
    }
  }

}