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 (2.7.1) (judge verdict: Wrong Answer)

x,y=gets.split.map!(&:to_i)
ans1=0
ans2=x
if x==1 ||x==2
  if x==1
    puts 0
  else
    puts 1
  end
else
  while true
  ans1=(ans2-y).abs
  if ans1>ans2
    ans1=ans2
    break
  end
  ans2=ans1
  end
end
puts ans1