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 Go (1.6) (judge verdict: Accepted)

package main

import "fmt"

func abs(num int) int {
	if num >= 0 {
		return num
	} else {
		return -num
	}
}

func main() {
	var N, K int
	fmt.Scan(&N, &K)

	var ans1, ans2 int
	ans1 = N - K*(N/K)
	ans2 = abs(N - K*((N/K)+1))
	if ans1 < ans2 {
		fmt.Println(ans1)
	} else {
		fmt.Println(ans2)
	}
}