import Data.List
z=zipWith
main=interact$unlines.f.lines
f x@(h:_)=sortBy((.(h!)).compare.(h!))x
x!y=last$foldl(#)[0..][1:[sum[1|s/=t]|t<-y]|s<-x]
x#y=scanl1(%)$z(%)x$z(+)y$4:x
x%y=min(1+x)y