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 Ruby (2.3.3) (judge verdict: Accepted)

line = gets.chop.split.map(&:to_i)
n = line[0]
k = line[1]


def minimal(n, k);
  tmp = Float::INFINITY
  tmp2 = 0
  if n > k
    tmp2 = n % k
  else
    tmp2 = n
  end
  while true do
    if tmp > tmp2
      tmp = tmp2
    else
      return tmp
    end
    tmp2 = (tmp2 - k).abs
  end
end
puts minimal(n, k)