open System

let rec binarySearch ng ok func =
        if abs (ok-ng) > 1 then 
            let mid = (ok+ng)/2
            if func mid then 
                binarySearch ng mid func 
            else 
                binarySearch mid ok func
        else 
            if func ok then Some(ok)
            else            None

let lowerBound (arr:'a[]) x =
    binarySearch -1 arr.Length (fun mid -> compare arr.[mid] x >= 0)
            
let arr =
    let rec f a =
        [|
            yield a
            if a < (int 1e9 + 5) then 
                yield! f (a*2)
        |]
    f 1       

let N = Console.ReadLine() |> int

let ans = 
    match lowerBound arr N with
    | Some(x) -> 
        let n1 = x
        let n2 = arr.[n1] - N
        n1 + n2                
    | None ->
        -1
    
ans
|> printfn "%i"