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 C# (judge verdict: Accepted)

using System;
using System.Linq;
class A
{
    static void Main()
    {
        double[] a = Console.ReadLine().Split().Select(double.Parse).ToArray();
        Console.WriteLine(Math.Sqrt((a[2]-a[0])*(a[2]-a[0])+(a[3]-a[1])*(a[3]-a[1])));
    }
}