1
Notice the missing top row of function keys. People have speculated that this top row may be replaced by an OLED touch screen.
Comparing the above photo to the Macbook keyboard, it would seem that the top row includes the escape key: http://cdn.macrumors.com/article-new/2014/11/retinamacbookkeyboard-800x484.jpg
If this is the case, any software developer that uses the escape key a lot may not be very happy.