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 <cmath>
#include <iostream>
#include <cstdio>
using namespace std;


int main()
{
	double a, b, c, d;
	cin >> a >> b >> c >> d;
    
	printf("%lf\n", sqrt(pow(c - a, 2) + pow(d - b, 2)));
	return 0;
}