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


int main(){
 cout<<fixed<<setprecision(12);
 double x1,y1,x2,y2;
 cin>>x1>>y1>>x2>>y2;
 double X=pow(x1-x2,2);
 double Y=pow(y1-y2,2);
 cout<< sqrt(X+Y)<<endl;
}

### 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(){
 cout<<fixed<<setprecision(12);
 double x1,y1,x2,y2;
 cin>>x1>>y1>>x2>>y2;
 double X=pow(x1-x2,2);
 double Y=pow(y1-y2,2);
 cout<< sqrt(X+Y)<<endl;
}

```