rank nation gold silver bronze total
rank
nation
gold
silver
bronze
total
number
first second
number
number
number
number
number text(text) number number number number
1 china (chn) 14 10 12 36
how many nations won no silver medals at all ?
WRB JJ NNS VBD DT NN NNS IN DT .
11
select count ( c2 ) from w where c4_number = 0