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>

int main()
{
  int x,k;
  int min,p_x,now;
  scanf("%d",&x);
  scanf("%d",&k);
 
  p_x = x;
  now = k - x;
  if(now<0) now*=-1;
  x = now;
  
  min = x;
  while(1){
    now = k - x;
    if(now<0) now*=-1;
    if(min>now){
      min = now;
      x = min;
    }
    else
      break;
  }
  if(min<p_x) printf("%d",min);
  else printf("%d",p_x);
  return 0;
}