using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

​

namespace IPGolf

{

    public class Program

    {

        static long f(params string[] a)

        {

            return Math.Abs(                                // At the end, make all values +ve.

                 a.Select(                                  // Go through both items in the array...

                    b =>                                    // Calling each one 'b'. 

                        b.Split('.')                        // Separating out each "." separated byte...

                        .Select(long.Parse)                 // Converting them to a long.

                        .Aggregate((c, d) => (c<<8) + d))   // Shift each byte along and add the next one.

                        .Aggregate((e,f) => e-f)            // Find the difference between the two remaining values.

                        )+1;                                // Add one to the result of Math.Abs.

        }

​

        public static void Main(string[] args)

        {

            Console.WriteLine(f("1.2.3.4", "1.2.3.5"));         // 2.

            Console.WriteLine(f("0.0.0.0","255.255.255.255"));  // 4294967296.

            Console.WriteLine(f("255.255.255.255","0.0.0.0"));  // 4294967296.

            Console.WriteLine(f("1.2.3.4","1.2.3.4"));          // 1.

            Console.WriteLine(f("56.57.58.59","60.61.62.63"));  // 67372037.

        }

    }

}

​