#include<bits/stdc++.h>
#define ll long long

using namespace std;

int main(){
	double x1,x2,y1,y2,s;
	
	cin>>x1>>y1>>x2>>y2;
	
	s=(x1-x2)*(x1-x2)+(y1-y2)*(y1-y2);
	s=sqrt(s);
	
	printf("%lf",s);
}

### 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>
#define ll long long

using namespace std;

int main(){
	double x1,x2,y1,y2,s;
	
	cin>>x1>>y1>>x2>>y2;
	
	s=(x1-x2)*(x1-x2)+(y1-y2)*(y1-y2);
	s=sqrt(s);
	
	printf("%lf",s);
}

```