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 CPP):

Solution:
#include <iostream>
#include <cmath>
using namespace std;


int main()
{	
	double x1, x2, y1, y2, x, y;
	cin >> x1 >> y1 >> x2 >> y2;	
	x = x2 - x1;
	y = y2 - y1;
	cout << fixed << sqrt(x*x+y*y) << endl;
	return 0;
}