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 did not win any silver medals ?
WDT NNS VBD-AUX RB VB DT NN NNS .
Antigua and Barbuda|Suriname|Cayman Islands|Saint Kitts and Nevis
select c2 from w where c4_number = 0