
import java.util.*;
public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    long N = sc.nextLong();
    long K = sc.nextLong();
    long ans =0;
    N = N%K;
    ans =N;
    for(int i=0;i<100;i++){
      N=Math.abs(N-K);
      if(N<ans){
        ans=N;
      }
    }
    System.out.println(ans);

  }
  

  
}

/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