"""

https://yukicoder.me/problems/no/314

dp

"""

N = int(input())

dp = [0,0,1]
mod = 10**9+7

for i in range(N):

    ndp = [0,0,0]

    ndp[0] += dp[2]
    ndp[1] += dp[0]
    ndp[2] += dp[0] + dp[1]

    dp = [x%mod for x in ndp]

print (sum(dp) % mod)