module Yuki

open System

let MOD = (int 1e9) + 7

(*
    Ken_1 -> A
    Ken_2 -> B
    Pa    -> C
*)

[<Struct>]
type State =
    { A : int
      B : int
      C : int }
    member __.Sum =
        ((__.A + __.B) % MOD + __.C) % MOD

let solve n =
    let rec f state =
        function
        | 0 -> state
        | n -> f { A = state.C; B = state.A; C = (state.A + state.B) % MOD } (n - 1)
    (f { A = 1; B = 0; C = 0 } (n - 1)).Sum

    
let N = Console.ReadLine() |> int

N
|> solve
|> Console.WriteLine