import math._

object Main {
  def main(args: Array[String]) {
    val sc = new java.util.Scanner(System.in)
    val n = sc.nextInt
    if (n == 1) {
      println(1)
      return
    }
    else if (n == 2) {
      println(2)
      return
    }

    val mod = 1e9.toInt + 7

    val dp = Array.fill(n+10)(0)
    dp(2) = 1
    dp(3) = 1
    for (i <- 2 to n-2) {
      dp(i+2) = (dp(i+2) + dp(i)) % mod
      dp(i+3) = (dp(i+3) + dp(i)) % mod
    }

    val a = dp(n).toLong
    val b = dp(n-1).toLong
    val c = dp(n-2).toLong
    val ans = (a + b + c) % mod
    println(ans)
  }
}