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.*;
 
public class Main {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);          
	
	double a = sc.nextDouble();
        double b = sc.nextDouble();
        double c = sc.nextDouble();
        double d = sc.nextDouble();
        double x = c - a;
        double y = d - b;
        double f = (x * x) + (y * y);
        double g = Math.sqrt(f);
        
	System.out.printf("%.6f\n", g);
 
	}
}