#include<iostream>
#include <math.h>
#include <stdio.h>

using namespace std;

int main(){
 double x1,y1,x2,y2;
 cin >> x1 >> y1 >> x2 >> y2;
 printf("%.5f", sqrt((x1-x2)*(x1-x2) + (y1-y2)*(y1-y2)));

}

### 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 <math.h>
#include <stdio.h>

using namespace std;

int main(){
 double x1,y1,x2,y2;
 cin >> x1 >> y1 >> x2 >> y2;
 printf("%.5f", sqrt((x1-x2)*(x1-x2) + (y1-y2)*(y1-y2)));

}

```