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)

min1=0
min2=0
def amb(n,k):
    min1=abs(n%k)
    min2=abs(min1-k)
    if min1==0 or min2==0:
        print(0)
    elif min1==min2:
        print(min1)
    elif min1>min2:
        print(min2)
    elif min1<min2:
        print(min1)

n,k=list(map(int,input().split()))
if n<k:
    print(n)
elif n==k:
    print(0)
else:
    amb(n,k)