import array

def main():
  dp = array.array("Q", [1,2,2])
  mod = 10**9 + 7
  N = int(input())

  if N <= 3:
    print(dp[N-1])
    return

  for n in range(3, N):
    dp.append((dp[n-3]+dp[n-2]) % mod)

  print(dp[-1])

main()