F35, which is the highlighter brush (pictured above). The brush is tapered with a point at the top. I know the shape varies from one brush to the next, but mine came pretty pointy which I love. This brush can be used to apply powder, blush and contour. I use it primarily to apply contour because you can get the tip right in the hollow of your cheeks. Also, I know you can use a rolling motion with the side of the brush to apply blush seamlessly, I have yet to try that. This is one of my favourite face brushes, it is genius, definitely more of a professional brush.
Do you have this brush?