#include<iostream>
#include<cmath>
using namespace std;
int main() {
    double xa, xb, ya, yb;
    cin >> xa >> ya >> xb >> yb;
    cout << fixed << sqrt(pow(xa-xb, 2) + pow(ya-yb, 2));
}

### Prompt

Please provide a Cpp coded solution to the problem described below:

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<iostream>
#include<cmath>
using namespace std;
int main() {
    double xa, xb, ya, yb;
    cin >> xa >> ya >> xb >> yb;
    cout << fixed << sqrt(pow(xa-xb, 2) + pow(ya-yb, 2));
}

```