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++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>
#include <iostream>
using namespace std;

int main() {
  long long n, k;
  long long ans;
  scanf("%lld %lld", &n, &k);
  // if (n >= k) {
  //   if (n%k == 0) {
  //     min = 0;
  //   } else {
    long long t = n % k;
    ans = t > k - t ? k -t : t;
      // ans = - (n % k - k) >= n % k ? n % k : - (n % k -k); 
  //   }
  // } else {
  //     min = - (n - k) >= n ? n : - (n - k); 
  // }
  printf("%d\n", ans);
  return 0;
}