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

int main(){
    double x1,x2,y1,y2;
    scanf("%lf %lf %lf %lf",&x1,&y1,&x2,&y2);
    printf("%.8lf\n",sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1)));
}


### 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<math.h>

int main(){
    double x1,x2,y1,y2;
    scanf("%lf %lf %lf %lf",&x1,&y1,&x2,&y2);
    printf("%.8lf\n",sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1)));
}


```