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(void)
{
  int N, K, num, min;
  int flag = 0;
  
  scanf("%d %d", &N, &K);
  
  num = N;
  min = N;
  do
  {
    num -= K;
    if(num < 0)
      num *= -1;
    
    if(flag == 0 || num < min)
    {
      min = num;
      flag = 1;
    }
    
    else if(num == min || num > min)
      flag = 2;
  } while(flag != 2);
  
  printf("%d\n", min);
  
  return 0;
}