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

namespace AtCoder
{
	class Program
	{
		static void Main(string[] args)
		{
			var Instance = new Question();
			Instance.Exec();
		}
	}

	public class Question
	{
		public void Exec()
		{
			var array = Console.ReadLine().Split(' ').Select(i => double.Parse(i)).ToArray();

			double distance = Math.Sqrt(Math.Pow(array[0] - array[2], 2.0) + Math.Pow(array[1] - array[3], 2.0));

			Console.WriteLine($"{distance:f6}");

			Console.ReadKey();
		}
	}
}