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 JavaScript (Node.js 12.16.1) (judge verdict: Accepted)

"use strict";

const main = (input) => {
    const spi = input.split('\n');
    const [n, k] = spi[0].split(' ').map(e => BigInt(e));

    const a1 = n % k;
    const a2 = a1 - k < 0 ? -(a1 - k) : a1 - k;

    console.log((a1 <= a2 ? a1 : a2).toString());
};

main(require("fs").readFileSync("/dev/stdin", "utf8"));