s = gets.chomp
size = []
n = s.size - 1
(0..n).each do |i|
  (i+1..n).each do |j|
    (j+1..n).each do |k|
      size << k - i + 1 if s[i] == 'c' && s[j] == 'w' && s[k] == 'w'
    end
  end
end
p size.empty? ? -1 : size.min