using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Please enter your age.");

        int userAge = Convert.ToInt32(Console.ReadLine());

        if(userAge > 19)

        {

            Console.WriteLine("You are an adult.");

        }

        else if(userAge < 19)

        {

            Console.WriteLine("You are a child.");

        }

    }

}

​