answer: #Person2# rents three pairs of skates, one for #Person2#, and the other two for kids, from #Person1#. #Person1# offers #Person2# suggestions about the safety of skating beginners.
documents: #Person1#: What can I do for you, young man?
  #Person2#: I need to rent three pairs of skates for the morning.
  #Person1#: What sizes do you need?
  #Person2#: One pair of 37, and two pairs of 21. One for me, and the other two for two kids.
  #Person1#: Here you are. And here are three crash helmets.
  #Person2#: Thanks. Well, those two kids are beginners. What should I do about their safety?
  #Person1#: Well, there are a lot to do, but nothing to worry about. First, make sure they don't go far from the railings.
  #Person2#: Oh, yeah, maybe I should ask them just to walk along the railings.
  #Person1#: That's a good idea. And remind them to be slow at the beginning, not to run into the railings.
  #Person2#: OK. Anything else?
  #Person1#: Never go to the center of the lake. The ice there is too thin to skate on.
  #Person2#: Got it. Thanks for reminding me. And, are there any intensive training courses?