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 Java7 (OpenJDK 1.7.0) (judge verdict: Accepted)

import java.util.*;
import java.io.*;
public class Main {
    public static void main(String[] args) throws Exception{
        
        Scanner sc = new Scanner(System.in);
  
        long n;
        long m;

         n = sc.nextLong();
      m = sc.nextLong();
       
      if(m>n){
        long k= Math.abs(m-n);
        if(k>=n){
          System.out.println(n);
        }
        else{
          System.out.println(k);
        }
      }else if(m==n){
         System.out.println(0);
      } else {
    	  if(m==0) {
    		  System.out.println(n);
    	  }else {
        long l = n/m;
        long rem = n%m;
        long x = Math.abs(rem-m);
         if(x>=rem){
          System.out.println(rem);
        }
        else{
          System.out.println(x);
        }
    	  }
      }
          
          
          
       
       
        
  }
}