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

int main() 
{
    double x1,y1,x2,y2;
    cin>>x1>>y1>>x2>>y2;
    
   printf("%.8f\n",sqrt(((x1-x2)*(x1-x2))+((y1-y2)*(y1-y2))));
    
return 0;
} 



### Prompt

Please create a solution in CPP 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;
    
   printf("%.8f\n",sqrt(((x1-x2)*(x1-x2))+((y1-y2)*(y1-y2))));
    
return 0;
} 



```