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;

class P
{
public static void Main()
{
//????????????????????????
            var a = Console.ReadLine().Split(' ');

            double x1 = Double.Parse(a[0]);
            double y1 = Double.Parse(a[1]);
            double x2 = Double.Parse(a[2]);
            double y2 = Double.Parse(a[3]);

            double x = x2 - x1;
            double y = y2 - y1;

            double D = Math.Sqrt(x * x + y * y);

            //??????
            Console.WriteLine("{0:f5}", D);
}
}