import java.util.Scanner;
 
public class Main{
 
	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		
		Scanner sc=new Scanner(System.in);
		
		long N_absolute=Math.abs(sc.nextLong());
		long K_absolute=Math.abs(sc.nextLong());
		long result=N_absolute;
		long hiki=0;

		result=N_absolute%K_absolute;
	
		if(result==0) {
			System.out.println(result);
		}else {
			hiki=result-K_absolute;
			hiki=Math.abs(hiki);
			if(result>hiki) {
				System.out.println(hiki);
			}else {
				System.out.println(result);
			}
		}
	
	}
}
/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