s = gets.chomp
min = 101

0.upto(s.size - 3) do |i|
  next unless (j = s.index('c', i))
  next unless (k = s.index('w', j))
  next unless (l = s.index('w', k + 1))

  min = [l - i + 1, min].min
end

puts min == 101 ? -1 : min