N = int(input())
DIV = 10 ** 9 + 7

dp = [0] * 3
dp[0] = 1

for i in range(N - 1):
  new_dp = [0] * 3
  new_dp[0] += dp[2]
  new_dp[1] += dp[0]
  new_dp[2] += dp[0] + dp[1]
  for j in range(3):
    new_dp[j] %= DIV
  dp = new_dp
  
print(sum(dp) % DIV)