// Learn more about F# at http://fsharp.org

open System

let rec pow a x =
    if x = 0L then 1L
    elif x = 1L then a
    elif x % 2L = 0L then pow (a * a) (x / 2L)
    else a * (pow a (x - 1L))

[<EntryPoint>]
let main argv =
    let [| xx; yy; h |] = stdin.ReadLine().Split() |> Array.map int64
    let x, y = Math.Min(xx, yy), Math.Max(xx, yy)

    let ans =
        seq {
            for a in 0L .. 16L do
                for b in 0L .. 16L do
                    // x を a 回折れるか
                    // x / 2^(a - 1) > h * 2^(a - 1)
                    if a = 0L
                       || x * 1000L > h * (pow 2L (a - 1L))
                                      * (pow 2L (a - 1L)) then
                        if b = 0L
                           || y * 1000L > h * (pow 2L a) * (pow 2L (b - 1L))
                                          * (pow 2L (b - 1L)) then yield (a, b)
        }
        |> Seq.map (fun tup -> (fst tup) + (snd tup))
        |> Seq.max
    printfn "%d" ans
    0 // return an integer exit code