#include<bits/stdc++.h>
using namespace std ;
int main () {
  double a , b , c , d ;
  cin >> a >> b >> c >> d ;
  double ans = sqrt(pow(a-c,2)+pow(d-b,2)) ;
  printf("%1f\n",ans);
}

### 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<bits/stdc++.h>
using namespace std ;
int main () {
  double a , b , c , d ;
  cin >> a >> b >> c >> d ;
  double ans = sqrt(pow(a-c,2)+pow(d-b,2)) ;
  printf("%1f\n",ans);
}

```