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>

int main(void)
{
	double x1,y1,x2,y2,r;
	scanf("%lf%lf%lf%lf",&x1,&y1,&x2,&y2);
	r=hypot((x2-x1),(y2-y1));
	printf("%8lf",r);
    return 0;
}