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: Wrong Answer)

def main():
  N,K = map(int, input().split())

  mod_min = 10**18

  if N >= K:
    N = N%K
  else:
    pass

  min_abs = 10*18

  while(True):
    tmp_abs = abs(N-K)
    if min_abs > tmp_abs:
      min_abs = tmp_abs
      N = min_abs
    else:
      break
  
  print(min_abs)

if __name__ == "__main__":
  main()