class Program
{
    static void Main(string[] args)
    {
        byte a = 2 | 4 | 8;
        byte b = (byte)~a;

        Console.WriteLine((b & 2) == 2);
        Console.WriteLine((b & 4) == 4);
        Console.WriteLine((b & 8) == 8);

        Console.WriteLine((b & 16) == 16);
        Console.WriteLine((b & 32) == 32);

        Console.Read();
    }
}

public class LayerMaskTest : MonoBehaviour
{
    public LayerMask layerMask;
    

    void OnEnable()
    {
        layerMask.value = ~layerMask.value;
    }
}

int layer = 1 << 7;
mMask = mMask & (~ layer);