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 endl '\n'
using namespace std;

int main(){
     long long n,k; cin>>n>>k;
     if(n==0){
        cout<<0<<endl;
     }
     else if(n!=0 && n>k && k>1){
        int x = n%k;
        long long rta = abs(x-k);
        cout<<rta<<endl;
     }
     else if(n<k){
        cout<<n<<endl;
     }
     else if(n==k){
        cout<<0<<endl;
     }
     else if(k==1 && n!=0){
        cout<<0<<endl;
     }
}