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 PyPy3 (2.4.0) (judge verdict: Accepted)

import sys
# 未解決(最後だけREになる)


def get():
    return list(map(int, input().split()))


a = get()
b = a[0]
c = a[1]
if b < c:
    if abs(b - c) < b:
        print(abs(b - c))
        sys.exit(0)
    else:
        print(b)
        sys.exit(0)
else:
    if a[0] % a[1] == a[1] or a[0] % a[1] == 0:
        print(0)
        sys.exit(0)
    else:
        if abs((a[0] % a[1]) - a[1]) < abs(((a[0] % a[1]) - a[1]) % a[1]):
            if abs(a[0] % a[1]) < abs((a[0] % a[1]) - a[1]):
                print(abs(a[0] % a[1]))
                sys.exit(0)
            else:
                print(abs((a[0] % a[1]) - a[1]))
                sys.exit(0)
        else:
            if abs(a[0] % a[1]) < abs(((a[0] % a[1]) - a[1]) % a[1]):
                print(abs(a[0] % a[1]))
                sys.exit(0)
            else:
                print(abs(((a[0] % a[1]) - a[1]) % a[1]))
                sys.exit(0)