rec.cs

public class Rectangle
{
    public int Height { get; set; }
    public int Width { get; set; }
    
    public virtual void SetHeight(int height)
    {
        this.Height = height;
    }
    public virtual void SetWidth(int width)
    {
        this.Width = width;
    }
    public virtual int CalculateArea()
    {
        return this.Height * this.Width;
    }
}

public class Square : Rectangle
{
    public override void SetHeight(int height)
    {
        this.Height = height;
        this.Width = height;
    }
    
    public override void SetWidth(int width)
    {
        this.Height = width;
        this.Width = width;
    }
}