s = gets.chomp

result = s.length
exist = false
for i in 0..s.length-3
    if s[i] == 'c'
        start = i
        for j in i+1..s.length-2
            if s[j] == 'w'
                for k in j+1..s.length-1
                    if s[k] == 'w'
                        result = [result,k-i+1].min
                        exist = true
                    end
                end
            end
        end
    end
end
puts exist ? result : -1