Another post about oxbridge.

I'm currently doing 3 A levels: Maths, politics and business. I'm not focused on doing any degrees with those subjects in mind. I'm planning to do 3 extra A levels which are the 3 sciences, Biology chemistry and physics. Neurology is the course which I'm hoping to do. Since I'll be going to university with additional A levels than the majority i.e oxbridge would I have a better chance to get in if I had 5 A levels (all Grade A), or does oxbridge focus on the top 3-4 A levels.

Note, I haven't done any of my A levels yet. I just started so I've been contemplating whether or not I should work hard and get into oxford with 5 A levels, or would I only need to focus on 3 top A levels.