<human>: This hasn't been a problem until recently, but for the past few months my apartment has been smelling of cigarette smoke a few days out of the week when I come home. I know my upstairs neighbor smokes, though when I spoke to her about it she claims she 'only smokes outside'. But this is a gross, deep apartment smoke smell, not a passing in the breeze waft. I spoke to my landlord about it, but she says she has called the neighbor who denies it, so won't do anything further. There are only three units in the house, one belonging to me, one to the smoking neighbor and the other my landlord keeps as an office space. She definitely doesn't smoke.

So, reddit, what would you do if it was you?

Can you condense the text into three sentences or less?
<bot>: Cigarette smell seeping into my apartment, upstairs neighbor denies smoking inside and landlord will not pursue further than a phone call.