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>
int main()
{
unsigned  long long int a,b,c;
  scanf("%d %d",&a,&b);
unsigned  long long  int d=a%b;
if (b%2==1)
   {
      if(d<=(b-1)/2)
      {
      c=d;  
      printf("%d",c);
      }
     else {c=b-d;
            printf("%d",c);
            }
    }
  
else
   {
      if(d<b/2) 
       {c=d;
        printf("%d",c);
        }
      else {c=b-d;
            printf("%d",c);
            }
    }
return 0;
}