output_description: If there does not exist an valid assignment that is consistent with s, print
  `-1`. Otherwise, print an string t in the following format. The output is
  considered correct if the assignment described by t is consistent with s.
  
    * t is a string of length N consisting of `S` and `W`.
    * If t_i is `S`, it indicates that the animal numbered i is a sheep. If t_i is `W`, it indicates that the animal numbered i is a wolf.
  
  * * *
input_description: The input is given from Standard Input in the following format:
  
      
      
      N
      s
attempt: io = STDIN
  $n=io.gets.chomp.to_i
  $s=io.gets.chomp
  
  $ans=' '*$n
  
  def check2(i)
    return true if $ans[i]==' '
    nxt = i==$n-1 ? 0 : i+1
    return true if $ans[i-1]==' ' || $ans[nxt]==' '
    rslt=case $s[i]
    when "o"
      if $ans[i]=="S"
        $ans[i-1]==$ans[nxt]
      else
        $ans[i-1]!=$ans[nxt]
      end
    else
      if $ans[i]=="S"
        $ans[i-1]!=$ans[nxt]
      else
        $ans[i-1]==$ans[nxt]
      end
    end
    # p ["check2",i,rslt,$s[i],$ans[i-1],$ans[i],$ans[nxt]]
    rslt
  end
  def check1(i)
    if i==$n
      if check2(i-1)
        return $ans
      else
        return false
      end
    else
      ["S","W"].each do |a|
        $ans[i]=a
        if check2(i-1)
          return true if check1(i+1)
        end
      end
      return false
    end
  end
  puts check1(0) ? $ans : -1
problem_description: Statement
  
  Snuke, who loves animals, built a zoo.
  
  There are N animals in this zoo. They are conveniently numbered 1 through N,
  and arranged in a circle. The animal numbered i (2≤i≤N-1) is adjacent to the
  animals numbered i-1 and i+1. Also, the animal numbered 1 is adjacent to the
  animals numbered 2 and N, and the animal numbered N is adjacent to the animals
  numbered N-1 and 1.
  
  There are two kinds of animals in this zoo: honest sheep that only speak the
  truth, and lying wolves that only tell lies.
  
  Snuke cannot tell the difference between these two species, and asked each
  animal the following question: "Are your neighbors of the same species?" The
  animal numbered i answered s_i. Here, if s_i is `o`, the animal said that the
  two neighboring animals are of the same species, and if s_i is `x`, the animal
  said that the two neighboring animals are of different species.
  
  More formally, a sheep answered `o` if the two neighboring animals are both
  sheep or both wolves, and answered `x` otherwise. Similarly, a wolf answered
  `x` if the two neighboring animals are both sheep or both wolves, and answered
  `o` otherwise.
  
  Snuke is wondering whether there is a valid assignment of species to the
  animals that is consistent with these responses. If there is such an
  assignment, show one such assignment. Otherwise, print `-1`.
samples: [{"input": "6\n    ooxoox", "output": "SSSWWS\n    \n\nFor example, if the animals numbered 1, 2, 3, 4, 5 and 6 are respectively a\nsheep, sheep, sheep, wolf, wolf, and sheep, it is consistent with their\nresponses. Besides, there is another valid assignment of species: a wolf,\nsheep, wolf, sheep, wolf and wolf.\n\nLet us remind you: if the neiboring animals are of the same species, a sheep\nanswers `o` and a wolf answers `x`. If the neiboring animals are of different\nspecies, a sheep answers `x` and a wolf answers `o`.\n\n![b34c052fc21c42d2def9b98d6dccd05c.png](https://atcoder.jp/img/arc069/b34c052fc21c42d2def9b98d6dccd05c.png)\n\n* * *"}, {"input": "3\n    oox", "output": "-1\n    \n\nPrint `-1` if there is no valid assignment of species.\n\n* * *"}, {"input": "10\n    oxooxoxoox", "output": "SSWWSSSWWS"}]