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) {
		try(Scanner sc = new Scanner(System.in)){
			double x1 = sc.nextDouble();
			double y1 = sc.nextDouble();
			double x2 = sc.nextDouble();
			double y2 = sc.nextDouble();
			
			double dx = x1-x2;
			double dy = y1-y2;
			
			System.out.println(Math.sqrt(dx*dx+dy*dy));
		}
	}
}