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 max (int a,int b)
{
if(a>b)
 return a-b;
 else
 return b-a;
}

int main(void){
long int n,k,c,ans,ANS;
scanf("%d %d",&n,&k);
 c=max(n,k);
 if(c>n)
 printf("%d",n);
 else{
 ans=max(c,k);
 do{
 ANS=ans;
 ans=max(ans,k);
 } while(ANS>ans);
printf("%d",ANS);}

return 0;
}