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<bits/stdc++.h>
//#include <iostream>
//#include <iomanip>
//#include <vector>
//#include <cmath>
//#include <algorithm>
using namespace std;


#define F first
#define PB push_back
#define MP make_pair

typedef unsigned long long ll;

ll p = pow(10, 9) + 7;




int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    unsigned long long x, k;
    cin >> x >> k;
    bool done = false;

    while(!done)
    {
        if(x > k)
        {
            x = x % k;
        }else
        {
            if(k - x < x)
            {
                x = x - k;
            }
            done  = true;
        }
    }
    cout << x << endl;


}