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;
  int kouho1, kouho2;
  int answer;
  
  scanf("%d %d", &N, &K);
  
  if(N > K && K != 1) {
    kouho1 = N % K;
    kouho2 = K - (N % K);
    if(kouho1 > kouho2) {
      answer = kouho2;
    }else {
      answer = kouho1;
    }
  }else if(K > N && K != 1) {
    kouho1 = N;
    kouho2 = K - N;
    if(kouho1 > kouho2) {
      answer = kouho2;
    }else {
      answer = kouho1;
    }
  }else if(N == K || K == 1) {
    answer = 0;
  }
  
  printf("%d", answer);
  
  return 0;
}