open System
type Sol() =
    member this.Solve() = 
        
        let N =stdin.ReadLine() |> int
        
        let rec f n =
           match n with
           | 0 -> 0
           | _ -> 1 + f (n/2)
        
        f (N-1) |> printfn "%d"
        
let mySol = new Sol()
mySol.Solve()