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>
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define MIN(a,b) ((a) <= (b) ? (a) : (b))
#define ALL(v) (v).begin(), (v).end()
#define SORT(v) sort( ALL(v) )

using namespace std;
using ll = long long;
using P = pair<int,int>;

ll gcd(ll a, ll b)
{
    if (b == 0)
        return a;
    return gcd(b, a % b);

}


int main()
{
    ll N,K ; cin>>N>>K;


    if(N==0)
    {
        cout << 0 <<endl;
        return 0;
    }

    if(N%K == 0 ){
        cout << 0 << endl;
        return 0;
    }


    if(N>K && N%K!=0){

        cout << 1 << endl;
        return 0;
    }

    else{

        ll val = K-N;
        if(val > N)cout<<N<<endl;
        else cout << val << endl;
    }
    return 0;
}