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)

num_list = [int(i) for i in input().split()]
min_list = []

if num_list[0] < num_list[1]:
    if (num_list[1] - num_list[0]) < num_list[0]:
        print(num_list[1] - num_list[0])
    else:
        print(num_list[0])
elif num_list[0] == num_list[1]:
    print(0)
elif num_list[1] % num_list[0] == 0:
    print(0)
else:
    kake_num = num_list[0] // num_list[1]
    check_num = num_list[0] - (num_list[1]*kake_num)
    min_list.append(check_num)
    min_list.append((num_list[1] - check_num))
    print(min(min_list))