public class Program
{
    public static void Main()
    {
        IPerson john = new Man("John", 36, true);
        Console.WriteLine(john.GetInfo());
    }

    public interface IPerson
    {
        string Name { get; set; }
        int Age { get; set; }
        string Gender { get; set; }
    }

    public abstract class Person : IPerson
    {
        public Person(string name, int age, string gender)
        {
            this.Name = name;
            this.Age = age;
            this.Gender = gender;
        }

        public string Name { get; set; }
        public int Age { get; set; }
        public string Gender { get; set; }

        public virtual string GetInfo()
        {
            return $"{this.Name}-{this.Age}";
        }

    }

    public class Man : Person
    {
        public Man(string name, int age, bool isBald)
            : base(name, age, "m")
        {
            this.IsBald = isBald;
        }

        public bool IsBald { get; set; }

        public override string GetInfo()
        {
            return $"{base.GetInfo()}-{this.IsBald}";
        }
    }
}