These 2 guys keep hitting on me?

So one of my neighbors has these 2 grandsons that stay with her for a few weeks during the summer, I am 16 and they are a few years older than me. Well every summer we have a 4th of July party for our whole neighborhood and they usually come to it. They are constantly following me and my friends around, making lewd comments and checking us out (but in a really creepy way) I have told them numerous times to eff off but they are very persistent. I have a bf but unfortunately he's away on vacation. I am tired of these guys. they're just being a - holes but its really annoying. What should I do? oh and their always smoking or drinking and its disguisting. definately don't want to be around them