what about brazil /south america adapter

The MacBook will run on 100-240 Volts and 50-60 Hz, so it will run virtually anywhere in the world if you have the correct AC adapter. You do not need a voltage converter.

The shop at the airport will have what you need as well as luggage shops, etc.

Most major hotels have adapters as well in the gift shops. I cannot remember exactly which adapter I used, but I got it at the airport store and it worked fine. This link may help as well:

brazil plug adapters wa-5, wa-9, wa-10, #1, #3, & #6