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;

class Main{

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

		
		
}