chars = gets.chomp.chars
max = chars.length - 1
w_count = 0
res = []
count = 1
0.step(max) do |i|
    next if chars[i] != "c"
    (i + 1).step(max) do |j|
        count += 1
        w_count += 1 if chars[j] == "w"
        if w_count == 2
            res << count
            break
        end
    end
    count = 1
    w_count = 0
end
puts res.length == 0 ? "-1" : res.min