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[] aegs) {
		Scanner sc=new Scanner(System.in);

		double x1=sc.nextDouble();
		double y1=sc.nextDouble();
		double x2=sc.nextDouble();
		double y2=sc.nextDouble();

		double kyori=Math.sqrt(Math.pow(x1-x2, 2)+Math.pow(y1-y2, 2));

		System.out.println(kyori);
		sc.close();
	}

}