import Data.List

f::Int->String->[(String,Int)]->Int
f n ans []=length(ans)-2
f n ans ((a,b):xs)
    |n<=b=f b a xs
    |otherwise=f n ans xs
main = do
       e<-getLine
       es<-getContents
       let xs=group $ sort $ lines es
           ys=zip (map head xs) (map length xs)
       print $ f 0 "" ys