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.IO;
using System.Linq;
using System.Collections.Generic;

public class Program
{

    public void Proc()
    {
        double[] inpt = Reader.ReadLine().Split(' ').Select(a => double.Parse(a)).ToArray();

        double ans = Math.Sqrt(Math.Pow(inpt[0] - inpt[2], 2) + Math.Pow(inpt[1] - inpt[3], 2));
        Console.WriteLine(ans.ToString("#0.0#############"));
    
    }


    public class Reader
	{
		private static StringReader sr;
		public static bool IsDebug = false;
		public static string ReadLine()
		{
			if (IsDebug)
			{
				if (sr == null)
				{
					sr = new StringReader(InputText.Trim());
				}
				return sr.ReadLine();
			}
			else
			{
				return Console.ReadLine();
			}
		}
		private static string InputText = @"






1.123 0.0 1.123 100.0


";
	}

	public static void Main(string[] args)
	{
#if DEBUG
		Reader.IsDebug = true;
#endif
		Program prg = new Program();
		prg.Proc();
	}
}