class Yukicoder
  def initialize
    s = gets.chomp
    n = s.size
    inf = 9999
    w1 = -1
    w2 = -1
    min_length = inf

    s.chars.reverse.each_with_index do |ch, index|
      if ch == 'w'
        if w2 == -1
          w2 = n - index - 1
        elsif w1 == -1
          w1 = n - index - 1
        else
          w1, w2 = (n - index - 1), w1
        end
      elsif ch == 'c' && w1 != -1
        min_length = [min_length, w2 - (n - index - 2)].min
      end
    end

    if min_length == inf
      puts -1
    else
      puts min_length
    end
  end
end

Yukicoder.new