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>

int main(){

    int i,j;
    int n,k, min;

    //----input----
    scanf("%d %d", &n, &k);
    
    //----mainFunction----
    min = 0;

    while(k != 1){

        if(n - k >= 0){
            n = n - k;
            //printf("%d\n", n);
        } else {
            n = - (n - k);
            //printf("%d\n", n);
        }

        if(n - k >= 0){
            min = n - k;
            if(min > n){
                break;
            }
        } else {
            min = - (n - k);
            if(min > n){
                break;
            }
        }
       
    }


    //----output----
    if(k != 1){
        printf("%d\n", n);
    } else {
        printf("%d\n", 0);
    }
     
  

    return 0;

}