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)

                   /**Bismillahir Rahmanir Rahim.**/
/*
         Md.Fagun Molla
         18ICTCSE006
         BSMRSTU(SHIICT)
*/
#include <bits/stdc++.h>
using namespace std;


#define  gcd(a,b)         __gcd(a,b)
#define  lcm(a,b)         (a*b)/gcd(a,b)
#define  ll               long long
#define  vi               std::vector<int>
#define  pb               push_back
#define  MAX              100007
#define  End              return 0;
#define  pi               acos(-1)

map<string,int>v;
int main () {
    ios_base::sync_with_stdio(false); cin.tie(0);cout.tie(0);
    ll n,k;
    cin>>n>>k;
    ll x=n%k;
    ll y=abs((n/k+1)*(k)-n);
    //cout<<x<<" "<<y<<endl;
    cout<<min(x,y)<<endl;
    End
}
/* pray for me
Do before die
*/