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: Runtime Error)

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp> // Common file
#include <ext/pb_ds/tree_policy.hpp> // Including tree_order_statistics_node_update
 
using namespace std;
using namespace __gnu_pbds;
 
#define debug(s) cout << #s << " = " << s << endl
#define all(v) (v).begin(), (v).end()
#define mem(a,val) memset(a, val, sizeof a)
 
#define maxn 100010
#define INF 1e15
#define ff first
#define ss second
#define endl '\n'
typedef long long ll;
 
//typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  ll n, k;
  cin >> n >> k;
  if (n >= k) cout << min(n % k, n % (n - k)) << endl;
  else cout << min(n, k - n) << endl;
}