using System;

​

public class Program

{

    public static void Main()

    {

        string gender = "Male";

        int age = 18;

        if (gender == "Male") // true

        {

            Console.WriteLine("Only males are allowed.");

​

            if (age >= 18) // true

                Console.WriteLine("I am 18+.");

            else

                Console.WriteLine("I am not 18+.");

        }

        else if (gender == "Female")

        {

            Console.WriteLine("Only females are allowed.");

        }

        else

        {

            Console.WriteLine("Unknown gender!");

        }

    }

}