strs = gets.chomp.scan(/c.*w.*w/)
if strs.length == 0
    puts "-1"
else
    chars = strs[0].chars
    max = chars.length - 1
    w1,w2 = false,false
    res = []
    count = 1
    0.step(max) do |i|
        next if chars[i] != "c"
        (i + 1).step(max) do |j|
            count += 1
            if chars[j] == "w" and not w1
                w1 = true
            elsif chars[j] == "w" and w1
                w2 = true
            end
            if w1 and w2
                res << count
                break
            end
        end
        count = 1
        w1,w2 = false , false
    end
end
puts res.min