import java.util.Scanner;

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

      System.out.print("Enter x y for the first point: ");
      double x1 = in.nextDouble();
      double y1 = in.nextDouble();
      System.out.print("Enter x y for the second point: ");
      double x2 = in.nextDouble();
      double y2 = in.nextDouble();

      double dx = ...;
      double dy = ...;
      double distance = ...;

      System.out.println("The distance is " + distance);
   }
}