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.io.IOException;
import java.util.Scanner;

class Main {

	public static void main(String[] args) throws IOException {

		Scanner scane = new Scanner(System.in);

		double px1 = scane.nextDouble();

		double py1 = scane.nextDouble();

		double p2x1 = scane.nextDouble();

		double p2y1 = scane.nextDouble();


		System.out.println(Math.hypot((p2x1-px1),(p2y1-py1)));

	}

}