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){
		Scanner scan = null;
		try{
			scan = new Scanner(System.in);
			double a,b,c,d;
			a = scan.nextDouble();
			b = scan.nextDouble();
			c = scan.nextDouble();
			d = scan.nextDouble();
			System.out.println(Math.hypot(a-c,b-d));
		}finally{
			if(scan!=null)scan.close();
		}
	}
}