s = gets.chomp
INF = 10 ** 20
ans = INF
(0..(s.size-3)).each do |i|
  next unless s[i] == 'c'
  ((i+1)..(s.size-2)).each do |j|
    next unless s[j] == 'w'
    ((j+1)..(s.size-1)).each do |k|
      if s[k] == 'w'
        ans = [ans, k - i + 1].min
      end
    end
  end
end
puts ans == INF ? -1 : ans