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.io.IOException;
import java.util.Scanner;
public class Main {
	public static void main(String[] args) throws IOException{
		Scanner sc = new Scanner(System.in);

		double x0 = sc.nextDouble();
		double y0 = sc.nextDouble();
		double x1 = sc.nextDouble();
		double y1 = sc.nextDouble();

		double xr = Math.abs(x1 - x0);
		double yr = Math.abs(y1 - y0);

		double ans = Math.sqrt(xr * xr + yr * yr);

		System.out.println(ans);

		sc.close();
	}
}