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)

function main(input) {
  var nums = input.split(' ');

  var N = parseFloat(nums[0], 10);
  var x = N;
  var memo = [x];
  var res = x;
  var K = parseFloat(nums[1], 10);

  if (K === 1) {
    console.log('0');
    return;
  }

  while (true) {
    console.log(K);
    x = Math.abs(x - K);
    console.log('memo:', memo, x);
    if (memo.indexOf(x) != -1) break;
    if (x < res) {
      res = x;
    }
    memo.push(x);
  }

  console.log(String(res));
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));