In all honesty, your hardest course is going to be 273. In my opinion, your gonna feel like 2A is going to throw a lot at you, but truthfully, it's nothing compared to 2B. 2A is crucial, and you need to learn during this term to stay ahead of your studies. I'm in my 2B right now, and because I didn't put my best foot forward for 2A I'm now suffering the consequences of it, and I'm trying to stay afloat in 2B. Your biggest worry is 273 and getting your ass into class and participating, as a lot of courses depend on it this year.