open System
open System.Text

let solve s =
    let len = s |> String.length
    
    let lengest_palin k =
        let rec loop i j l =
            if 0 <= i && i < len && 0 <= j && j < len
                && s.[i] = s.[j]
            then loop (i - 1) (j + 1) (l + 2)
            else l
        [ loop (k - 1) (k + 1) 1; loop k (k + 1) 0 ]

    [ for k in 0..((s |> String.length) - 1) do
        yield! lengest_palin k
        ]
    |> List.filter ((<>) len)
    |> List.fold max 1

[<EntryPoint>]
let main argv =
    let s = Console.ReadLine()
    printfn "%d" <| solve s

    //exit
    0