I don't know where on earth the ants are coming from. How do I take rid of them? I live in a 3-story townhouse. There are no ants...

I live in a 3-story townhouse. There are no ants on the first or second floors. On the third floor, surrounded by one of the bedrooms, there are lots of ants on the windowsill. In front of the townhouse, within is a tall tree, the branches of which are massively close to the window of the bedroom contained by question. I hold a hard time believing that the ants climb the tree, after walk across the branches, onto the leaves, and next onto the windowsill. Where are they coming from? There is absolutely no food or drinks that are ever brought into that bedroom, and the bedroom right subsequent door doesn't have ants that collect on its windowsill.

What's going on here?
Answers:    They own a trail up the tree to the room. Buy Ant Bait, which is very inexpensive, and put it below the tree and within the room that has ants. They will fetch it to their anthill and it will kill the unbroken colony. Look around the tree and see if you can find the anthill. You can also buy granules to assassinate them outside.
Good Luck!
I don't know if ants climb trees or what but if they aren't on the 1st or 2nd floor, they must climb something...either means of access cinnamon is great way to find rid of ants. Plus Natural. Ants follow their trail by each other's scent. Put some cinnamon on the windowsill and they will lose respectively other's scent. Plus where ever else you believe they are. Good luck!