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>
using namespace std;

int main(){

    string num;
    int k;

    cin>>num>>k;

    // int n =  strlen(num);

    long long int mod = 0;

    for(int i = 0 ; i < num.size() ; i++){

        int digit = num[i] - '0';
        mod = mod*10 + digit;
        mod = mod%k;
    }

    // int num1 = stoi(num);
 
 if(mod>abs(k-mod)){
     cout<<abs(k-mod);
 }

 else{
     cout<<mod;
 }
    return 0;
}