# frozen_string_literal: true

S = gets.chomp

=begin
result = S.size
exist = false
S.scan(/(?=(c[^cw]*?w[^w]*?w))/).each do |m|
  result = [result, m[0].to_s.size].min
  exist = true
end
=end

exist = false
result = ((S.scan(/(?=(c[^cw]*?w[^w]*?w))/).map do |m|
  exist = true
  m[0].to_s.size
end) + [S.size]).min

RESULT = exist ? result : -1

puts RESULT