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[] args) {
		try (Scanner sc = new Scanner(System.in);) {
			double x1 = sc.nextDouble();
			double x2 = sc.nextDouble();
			double y1 = sc.nextDouble();
			double y2 = sc.nextDouble();
			
			double dis = Math.sqrt(Math.pow(y1 - x1, 2) + Math.pow(y2 - x2, 2));
			System.out.println(dis);
		}
	}
}