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.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

public class Main {

	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		
		final double x1 = sc.nextDouble();
		final double y1 = sc.nextDouble();
		final double x2 = sc.nextDouble();
		final double y2 = sc.nextDouble();
		
		System.out.printf("%.7f\n", Math.sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2)));
		
	}
}