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(){

  int N,K;
  int N1;

  scanf("%d %d",&N,&K);
 if(K != 1 && K != 0){

 
  if(N > K){
    N = N%K;
  }
 if(N != 0){
  if(K%N == 0){
    N = 0;
  }
 }
else{}

  N1 = K - N;
  
  
  if(N >= N1){
    printf("%d",N1);
  }
  else{
    printf("%d",N);

  }
 }
else if (K == 1){
  printf("0");
}

else{
  printf("%d",N);
}

  return(0);
}