str = gets.chomp.split(//)
min = 1000
len = 1000
str.size.times{|i|
    wflag = 0
    if str[i]=='c'
        (i..(str.size)).each{|j|
            if str[j]=='w' && wflag == 0
                wflag = 1
            elsif str[j]=='w' && wflag == 1
                min = j-i+1 if min > j-i+1
                break
            end
        }
    end
}


if min == 1000
    puts '-1'
else
    puts min
end