using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var a = new A();

        a.SetA = 123;

        Console.WriteLine(a.GetA);

    }

}

​

public class A

{

    private int _a;

    public int GetA { get { return _a;} private set { _a = value; }}

    public int SetA { private get { return _a;} set { _a = value; }}

}

​