Which should I take first: 261 or 271?

I'm starting this Fall in 162 and coming in with 161 and 225 waived. Since I'm working full-time as a Software Engineer, I will be taking 1 class per quarter. I was wondering what I should take in the Winter quarter? I'm debating between 261 and 271. Not sure if taking Data Structures (261) prepares you for Assembly (271) or is it the other way around?