import java.io.*;
import java.util.*;
import javax.swing.JOptionPane;

//Josh
public class distancejopanefmt
	{
		public static void main(String[]args)
            {
		String X1str;
		String X2str;
		String Y1str;
		String Y2str;
		double X1;
		double X2;
		double Y1;
		double Y2;

        X1str = JOptionPane.showInputDialog("Enter x1:");
		X1 = Double.parseDouble(X1str);

		X2str = JOptionPane.showInputDialog("Enter x2:");
		X2 = Double.parseDouble(X2str);

		Y1str = JOptionPane.showInputDialog("Enter y1:");
		Y1 = Double.parseDouble(X1str);

		Y2str = JOptionPane.showInputDialog("Enter y2:");
		Y2 = Double.parseDouble(X1str);

		double distance = Math.sqrt((X1-X2)*(X1-X2)+(Y1-Y2)*(Y1-Y2));

		JOptionPane.showMessageDialog(null,distance,"Distance is:",
		JOptionPane.INFORMATION_MESSAGE);

		System.exit(0);

		}

	}