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>
using namespace std;

int main() {
  
  vector<int64_t> N;
  int64_t K;
  cin >> N.at(0) >> K;
  
  int64_t i = 0;
  
  while (true) {
    N.at(i + 1) = N.at(i) - K;
    if (N.at(i + 1) < 0) {
      N.at(i + 1) *= (-1);
      if (N.at(i + 1) < N.at(i)) {
        cout << N.at(i + 1) << endl;
      }
      else {
        cout << N.at(i) << endl;
      }
      break;
    }
  i++;
  }
}