s=gets.chomp
n=s.size
maxl=0
(0...n).each{|i|
    (i+1..n).each{|j|
        if(i==0 && j==n)
            next
        end
        ss = s[i,j-i]
        if ss==ss.reverse
            l = ss.size
            maxl = [maxl,l].max
        end
    }
}
puts maxl