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) {

		try (Scanner sc = new Scanner(System.in);) {
			
			double x1 = sc.nextDouble();
			double y1 = sc.nextDouble();
			double x2 = sc.nextDouble();
			double y2 = sc.nextDouble();
			
			double distance = Math.sqrt((x2- x1) * (x2- x1) + (y2 - y1) * (y2 - y1));
			
			System.out.format("%.6f\n", distance);
		}
	}
}