using System;

public class Base
{
	public virtual string Foo { get; }
	
	public Base()
	{
		Console.WriteLine("Base()");
		Foo = "value from Base()";
		Console.WriteLine($"Foo = {Foo}");
	}
}
public class Derived : Base
{
	public override string Foo { get; } = "value from Derived init";
}

public class Test
{
	public static void Main()
	{
		Base x = new Derived();
		Console.WriteLine($"main: {x.Foo}");
	}
}