Conditional Formatting with golf skins

I have seen this issue addressed repeatedly on various threads. I actually have a function that works for my excel program on my personal computer, but the laptop we are using at the golf course only has Open Office because the owner is Scrooge McDuck. Here is the formula I use on my Skins program in Excel if I were looking at A1:A20

=AND(A1=MIN($A$1:$A$20),COUNTIF($A$1:$A$20,A1)=1)

How would I want to write this formula if it were in Open Office and not Excel? Every time I try to copy the program on to the computer at the course, it does not highlight the lowest score in the column properly. I basically want nothing to be highlighted unless there is a unique low score. If the lowest score is unique, I want it highlighted, but if it is tied, I want it left alone. Thanks a bunch. I am sure this is child's play for everyone here.

That took care of it. Thanks for your time. Haven't had to deal with Openoffice that much.