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.*;
public class Main {//ここが Main になっている
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        // Long N = sc.nextLong();
        // Long K = sc.nextLong();
        Long N = Long.parseLong(sc.next());
        Long K = Long.parseLong(sc.next());
        Long next_n;
        while (true) {
            next_n = Math.abs(N - K);
            if (next_n <= N){
                N = next_n;
                continue;
              }
            if (next_n >= N)
              {
                System.out.println(N);
                break;
              }
        }
    }
}
// 2147483647
// 10000000000000000