Problem: 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

Solution (in CPP):

Solution:
#include <stdio.h>
#include <math.h>
#define sqr(x) ((x) * (x))

int main(void){
double x1, y1, x2, y2;
scanf("%lf%lf%lf%lf",&x1,&y1,&x2,&y2);
printf("%f\n",sqrt(sqr(x2 - x1) + sqr(y2 - y1)));
return 0;
}