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 9.2.1) (judge verdict: Wrong Answer)

#include<stdio.h>
#include<stdlib.h>
int main() {
  long int n,k;
  scanf("%ld %ld",&n,&k);
  int dvide;
  dvide = n / k;
  if (dvide != 0) {
    if (n == dvide * k) {
      n = 0;
    }
    else {
    n = n - dvide * k;
    if (abs(n - k) < n) {
      n = abs(n - k);
    }
  }
}
  else {
    for (;abs(n - k) < n;) {
      n = abs(n - k);
    }
  }
  printf("%ld",n);
}