using System;

​

​

public class Program

{

    public static void Main()

    {

        var perm = Permissions.Software().WebTools().Admin().GetString();       

        Console.WriteLine(perm);

    }

}

​

public sealed class Permissions : ISoftware, IWebTools, IGetString

{

        private string result = "software" ;

​

        public static ISoftware Software()

        {           

            return new Permissions();

        }

​

        public IWebTools WebTools()

        {   

            this.result += ".webtools";

            return this;

        }

        public IGetString Admin()

        {   

            this.result += ".admin";

            return this;

        }

        public string GetString()

        {          

            return result;

        }       

}

​

public interface ISoftware

{

     IWebTools WebTools();

}

​

public interface IWebTools : IGetString

{

     IGetString Admin();

}

​

public interface IGetString

{

     string GetString();

}

​

​