Friends Late Daily

In my team there is a development team and there is 4 people in this team. The thing is 3 person out of 4 will be late daily. One example, they tell me they go back late so they come in late and the other day when I went back later than them, I found out they go back at around 6 or 615 and the next day they come in @ 10 or 1030am!

I mean this is really not fair as if you do OT means you are the problem and you don't know how to prioritize your work. They told me because they work longer means they can come in later. But last time or even now when I do OT, I still come in the same time the next day. I guess there is starting to be a feeling of unfairness by me and a friend of mine. But what can I do? Nothing. They still win team award the other day. Well for everyone note, to the perspective of those dudes from macha land, if you work longer hours and you can be doing nothing, you are actually performing.