import Data.List
main=do
    ctx<-getContents
    print $ length $ dup $ sort [read x::Int|x<-tail (lines ctx)]
dup :: [Int]->[Int]
dup []=[]
dup (x:y:xs)=if x==y then dup (xs) else x:dup (y:xs)
dup (x:[]) = [x]
