Problem:
Distance

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.

Sample Input

0 0 1 1

Sample Output

1.41421356

Solution in PHP (judge verdict: Wrong Answer)

<?php

class Distance
{
    public function __construct(Point $point1, Point $point2)
    {
        $this->point1 = $point1;
        $this->point2 = $point2;
    }

    public function compute()
    {
        return sqrt(
            pow($this->point2->x() - $this->point1->x(), 2)
          + pow($this->point2->y() - $this->point1->y(), 2)
        );
    }
}

class Point
{
    private $x;
    private $y;

    public function __construct($x, $y)
    {
        $this->x = $x;
        $this->y = $y;
    }

    public function x()
    {
        return $this->x;
    }

    public function y()
    {
        return $this->y;
    }
}

fscanf(STDIN, '%d %d %d %d', $x1, $y1, $x2, $y2);

echo (new Distance(new Point($x1, $y1), new Point($x2, $y2)))
    ->compute(), PHP_EOL;