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: Accepted)


import java.io.*;
import java.util.*;

public class Main {


    public static void main(String[] args) throws IOException {
        FastScanner in = new FastScanner();
        long n = in.nextLong();
        long k = in.nextLong();
        n = n % k;
        in.out.println(Math.min(Math.abs(n - k), n));
        in.out.close();
    }
}


class FastScanner {
    BufferedReader br;
    StringTokenizer st = new StringTokenizer("");
    PrintWriter out;

    FastScanner() {
        br = new BufferedReader(new InputStreamReader(System.in));
        out = new PrintWriter(System.out);
    }

    FastScanner(String in, String out_) throws FileNotFoundException {
        br = new BufferedReader(new FileReader(in));
        out = new PrintWriter(out_);
    }

    String next() throws IOException {
        while (st == null || !st.hasMoreTokens()) st = new StringTokenizer(br.readLine());
        return st.nextToken();
    }

    int nextInt() throws IOException {
        return Integer.parseInt(next());
    }

    long nextLong() throws IOException {
        return Long.parseLong(next());
    }
}