public class MyClass
{
    private int _what;
    public int Property
    {
        get
        {
            var lol = 0;
            lol += 100500;
            return lol;
        }
        set
        {
            _what = value;
            if (_what < 100500)
            {
                _what += 100500;
            }
        }
    }
}