#include <bits/stdc++.h>
using namespace std;

int	main()
{
	double x1, y1, x2, y2;
	cin >> x1 >> y1 >> x2 >> y2;
	cout << fixed << setprecision(8) << hypot(x1 - x2, y1 - y2) << endl;
}


### Prompt

Your task is to create a CPP solution to the following 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

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;

int	main()
{
	double x1, y1, x2, y2;
	cin >> x1 >> y1 >> x2 >> y2;
	cout << fixed << setprecision(8) << hypot(x1 - x2, y1 - y2) << endl;
}


```