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;

class Main {

	public static void main(String[] args) {

		double x1, y1, x2, y2;

		Scanner stdIn = new Scanner(System.in);

		x1 = stdIn.nextDouble();
		y1 = stdIn.nextDouble();
		x2 = stdIn.nextDouble();
		y2 = stdIn.nextDouble();

		System.out.println(Math.sqrt(Math.pow((x2 - x1), 2) + Math.pow((y2 - y1), 2)));

		stdIn.close();
	}
}