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 sc = new Scanner(System.in);
		double x1= sc.nextDouble(),y1= sc.nextDouble(),x2=sc.nextDouble(),y2=sc.nextDouble();
		double xd= Math.abs((x1-x2));
		double xd2 = Math.pow(xd, 2);
		double yd = Math.abs((y1-y2));
		double yd2 = Math.pow(yd, 2);
		double distance = Math.sqrt(xd2+yd2);
		System.out.printf("%9f",distance);
		System.out.println();
	}
}