import Data.Maybe

main = do
  _ <- getLine
  s <- getLine

  putStrLn $ h $ catMaybes [g a b s | a<-"SW", b<-"SW"]
  
  where
    h [] = "-1"
    h a = head a
    g a b xs = if b == rl && a == (last ri) then Just ri else Nothing
      where
        r = f a b xs
        ri = init r
        rl = last r
    f _ b [] = [b]
    f 'S' 'S' ('o':xs) = 'S' : (f 'S' 'S' xs)
    f 'S' 'S' ('x':xs) = 'S' : (f 'S' 'W' xs)
    f 'W' 'S' ('o':xs) = 'S' : (f 'S' 'W' xs)
    f 'W' 'S' ('x':xs) = 'S' : (f 'S' 'S' xs)
    f 'S' 'W' ('o':xs) = 'W' : (f 'W' 'W' xs)
    f 'S' 'W' ('x':xs) = 'W' : (f 'W' 'S' xs)
    f 'W' 'W' ('o':xs) = 'W' : (f 'W' 'S' xs)
    f 'W' 'W' ('x':xs) = 'W' : (f 'W' 'W' xs)
