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)

N, K = map(int, input().split())
j = 0
i = 1
A = 1000000000000000001
B = 1000000000000000002
C = 1000000000000000003
if N<K:
    print(N)
elif N==K:
    print(0)
elif N%K==0:
    print(0)
else:
    N = N%K
    while j==0:
        #print(N)
        #print("aaa")
        N = N-K
        N = abs(N)
        if i%3==0:
            A = N
        elif i%3==1:
            B = N
        elif i%3==2:
            C = N
        
        if A==C:
            if A<=B:
                print(A)
            else:
                print(B)
            j+=1
        elif B==A:
            if A<=C:
                print(B)
            else:
                print(C)
            j+=1
        elif B==C:
            if B<=A:
                print(C)
            else:
                print(A)
            j+=1
        i+=1