What kind of sentence structure is this: when i first came here, i didn’t like the citizens because they were different, but once i got to know them, they weren’t so bad.
why?

Compound-complex sentence because "When I first came here" Isn't a full sentence. ''I didn't like the citizens because they were different" is a compound. 
 
I think. I know it is a compound sentence, but from what I see it looks complex as well. 

Яне знаю i don’t know,i is russia

D. death in the afternoon