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;
public class Main{
 public static void main(String[] args) {
   Scanner kbd = new Scanner(System.in);
   long n =kbd.nextLong();
   long k =kbd.nextLong();
   long M=0;
   long m=n;

     if(k==1){
       System.out.println("0");
     }else{
     if(n-k>0){
       M=n-k;
     }else{
       M=-(n-k);
     }
     if(M<m){
       m=M;
     }
     if(m-k>0){
       M=m-k;
     }else{
       M=-(m-k);
     }
     while(m>M){
     if(M<m){
       m=M;
     }
     if(m-k>0){
       M=m-k;
     }else{
       M=-(m-k);
     }
}

   System.out.println(m);
 }
 }
}