s = gets.chomp.split("")
c, w1, w2 = -1, -1, -1
s.each_with_index {|x, i|
  case x
  when "c"
    c = i
  when "w"
    if c != -1
      if w1 == -1
        w1 = i
      else
        if w2 == -1
          w2 = i
        end
      end
    end
  end
}
if c == -1 ||
   w1 == -1 ||
   w2 == -1
  puts -1
else
  puts w2 - c + 1
end