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 C# (.NET Core 3.1.201) (judge verdict: Accepted)

using System;

class Program
{
    static void Main(string[] args)
    {
        var input = Console.ReadLine().Split(" ");
        var N = long.Parse(input[0]);
        var K = long.Parse(input[1]);

        var rem = N % K;
        if (rem == 0) Console.WriteLine(0);
        else
        {
            if (rem < Math.Abs(rem - K)) Console.WriteLine(rem);
            else Console.Write(Math.Abs(rem - K));
        }
    }
}