rank nation gold silver bronze total
rank
nation
gold
silver
bronze
total
number
number
number
number
number
number text number number number number
1 puerto rico 17 27 13 57
which nations won only bronze medals ?
WDT NNS VBD RB NN NNS .
Cayman Islands|Saint Kitts and Nevis
select c2 from w where c5_number = c6_number