Problem: Write a program which calculates the distance between two points P1(x1, y1) and P2(x2, y2).



Input

Four real numbers x1, y1, x2 and y2 are given in a line.

Output

Print the distance in real number. The output should not contain an absolute error greater than 10-4.

Example

Input

0 0 1 1


Output

1.41421356

Solution (in JAVA):

Solution:
import java.util.Scanner;
public class Main
{
	public static void main(String args[])
	{
		Scanner input = new Scanner(System.in);
		double x = input.nextDouble();
		double y = input.nextDouble();
		double x1 = input.nextDouble();
		double y1 = input.nextDouble();
		System.out.println( Math.sqrt((x-x1)*(x-x1)+(y-y1)*(y-y1)));
		input.close();
	}
}