// "static void main" must be defined in a public class.
import java.util.*;
public class Main {
    public static void main(String[] args) {
       Scanner sc = new Scanner(System.in);
        long x = sc.nextLong();
        long y = sc.nextLong();
        long a = x%y;
        long p = Math.min(a,y-a);
        
        
        
        System.out.println(p);
    }
}

/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