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 (GCC 5.4.1) (judge verdict: Accepted)

#include<stdio.h>

int zetai(int num);

int main() {
    
    long n,k,ans,a;
    scanf("%ld %ld",&n,&k);
    if(n > k) {
        a = n % k;
    } else {
        a = n;
    }
    if(a < k - a) {
        ans = a;
    } else {
        ans = k-a;
    }

    printf("%ld\n",ans);

    return 0;
}

int zetai(int num) {
    if(num < 0) {
        num *= -1;
    }
    return num;
}