#include<stdio.h>
#include<stdbool.h>
#include <math.h>
int main(void){
 double x1,y1,x2,y2;
 scanf("%lf %lf %lf %lf", &x1, &y1, &x2, &y2);
 printf("%.8f\n",sqrt(pow(fabs(x1-x2),2)+pow(fabs(y1-y2),2)));
 return 0;
}


### 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<stdio.h>
#include<stdbool.h>
#include <math.h>
int main(void){
 double x1,y1,x2,y2;
 scanf("%lf %lf %lf %lf", &x1, &y1, &x2, &y2);
 printf("%.8f\n",sqrt(pow(fabs(x1-x2),2)+pow(fabs(y1-y2),2)));
 return 0;
}


```