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.*;
class Main {
	public static void main (String[] args) throws java.lang.Exception {
		Scanner sc = new Scanner(System.in);
		double x1 = sc.nextDouble(), y1 = sc.nextDouble(), x2 = sc.nextDouble(), y2 = sc.nextDouble();
		System.out.printf("%.9f\n", Math.sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2)));
	}
}