module Yuki

open System

let inline ret x = Some x
let inline (>>=) (m: Option<'a>) f =
    match m with
    | Some x -> f x
    | None -> None

type MaybeBuilder () =
    member __.Return(x) = ret x
    member __.Bind(m, f) = m >>= f

let maybe = MaybeBuilder ()

let solve n =
    let num2list n =
        let rec f acc n =
            if n < 10 then n :: acc
            else f (n % 10 :: acc) (n / 10)
        f [] n
    let list2num xs =
        let rec f acc =
            function
            | [] -> acc
            | x :: xs -> f (acc * 10 + x) xs
        f 0 xs
    let swap idx1 idx2 xs =
        xs
        |> List.mapi (fun i v ->
            match i with
            | _ when i = idx1 -> xs.[idx2]
            | _ when i = idx2 -> xs.[idx1]
            | _ -> v)        

    let digits = num2list n
    let indexedDigits = List.indexed digits
    let maxDigit = List.max digits
    maybe {
        let! swapLeftIdx =
            indexedDigits
            |> List.tryFind (fun (_, x) -> x <= maxDigit)
            |> function
            | Some (idx, _) -> Some idx
            | None -> None
        let swapRightIdx =
            indexedDigits
            |> List.findBack (fun (_, x) -> x = maxDigit)
            |> fun (idx, _) -> idx
        return digits |> swap swapLeftIdx swapRightIdx |> list2num
    }
    |> function
    | Some x -> x
    | None -> n

let N = int <| Console.ReadLine()

solve N
|> Console.WriteLine