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 <iostream>
#include <stdio.h>
#include <cmath>

using namespace std;
int main () {
	double x1,y1,x2,y2;
	cin >> x1 >> y1 >> x2 >> y2;
	printf("%.6f\n",sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1)));
}