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 v5.12) (judge verdict: Wrong Answer)

"use strict"
function main(arg) {
    var tmp = arg.trim().split("\n")[0].split(" ").map(Number)
    var N = tmp[0]
    var K = tmp[1]
    // var x = N
    // for (var i = 0; i < 1000; i++) {
    //     var t = Math.abs(x - K)
    //     if (t < x) {
    //         x = t
    //     } else {
    //         break
    //     }
    // } 
    var npk = N % K
    // console.log(x)
    // console.log(npk)
    console.log(
        Math.min(npk, Math.abs(npk - K))
    )
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));