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: Wrong Answer)

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
int main(void){
  long int initial_value = 0;
  long int drawn_number = 0;
  long int distance = 0;
  scanf("%ld %ld",&initial_value, &drawn_number);
  if (initial_value > drawn_number){
    distance = initial_value % drawn_number;
  } else {
    distance = drawn_number;
  }
  long int revice_distance = abs(initial_value - distance);
  long int min_number = fmin(distance, revice_distance);
  min_number = fmin(min_number, initial_value);
  printf("%ld",min_number);
  return 0;
}