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 C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>
#include<math.h>
#include<stdlib.h>

int main(){
	long long n, k, eq=0, eq2=0;
	scanf("%lld %lld", &n, &k);
	if(n<k)
		printf("%lld", n);
	else if (n%k==0)
		printf("0");
	else if(n<k){
		eq= k-n;
		if(eq>n)
			printf("%lld", eq);
		else
			printf("%lld", n);
	}
	else{
		eq2= n%k;
		printf("%lld", k-eq2);
	}
	printf("\n");
    return 0;
}