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: Accepted)

#include <stdio.h>
#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>
using namespace std;
 
int main(int argc, const char * argv[]) {
 
 
 
    cin.tie(0);
    ios::sync_with_stdio(false);
 
    /////////////////////
    // Write code below /
    /////////////////////
    long long int n,k;
    
    cin >>n>>k;
    
    n=n% k;
    while(1){
        if(n-k < n && n-k > 0){
            n = n-k;
        }
        else if(k-n < n && k-n > 0){
            n = k-n;
        }
        else
            break;
    }
    cout <<n<<"\n";
    
    return 0;
}