import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

	    long result = execute(sc.nextLong(),sc.nextLong());
        System.out.println(result);
    }

    public static long execute(long n, long k){
        long plusTreated = n % k;
        long minusTreated =Math.abs( plusTreated - k);
        long treated = Math.min(plusTreated,minusTreated);
        if(n > treated) return execute(treated,k);
        return treated;
    }
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz