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;
import java.util.Arrays;

class Main{
	public static void main(String[] args){
		Scanner scanner = new Scanner(System.in);
		double a_1 = scanner.nextDouble();
		double b_1 = scanner.nextDouble();
		double a_2 = scanner.nextDouble();
		double b_2 = scanner.nextDouble();

		double x = (a_1 - a_2) *  (a_1 - a_2) + (b_1 - b_2) *  (b_1 - b_2);

		System.out.println(String.format("%.5f",Math.sqrt(x)));
	}
}