// yukicoder My Practice
// author: Leonardone @ NEETSDKASU

open System

let n = int64(Console.ReadLine())

let md = 1000000007L

let rec f a b c n =
    if n = 0L then
        (a + b + c) % md
    else
        f ((b + c) % md) a b (n - 1L)

printf "%d" <| f 0L 1L 0L (n - 1L)