import Control.Monad
import Data.Bool
import Data.Maybe
import qualified Data.ByteString.Char8 as B
main=putStrLn.solve.B.lines=<<B.getContents
solve[ns,s]=if null r then "-1" else fromJust(head r)where
  r=filter isJust.map(\ab->g ab.B.foldr f ab$s).replicateM 2$"SW"
  n=fst.fromJust.B.readInt$ns
  f s r@(a:b:cs)=(bool 'W' 'S'$(a==b)==(s=='o')):r
  g[c,d](a:b:cs)=bool Nothing(Just$take n$b:cs)$a==c&&b==d