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 Python (3.4.3) (judge verdict: Accepted)

import numpy as np
import fractions
N, K = [int(i) for i in input().split(' ')]

if N == 0:
	result = 0
elif K == 0:
	result = N
elif N % K == 0:
	result = 0
elif K % N == 0:
	result = K/N if N > K/N else N
elif N > K:
  result = N % K if N % K < K - N % K else K-N%K
elif N < K:
  result = K-N if N > K - N else N
  
print("{}".format(result))

#lis = np.array([int(n) for n in input().split(' ')])
#print("{} {}".format(sum(lis) / 4 / int(M), lis[int(M)-1]))

#count = sum(sum(lis) / 4.0 / int(M) <= lis)