N=int(input())

dp=[[0]*3 for i in range(N)]
dp[0][1]=1

for i in range(N-1):
    dp[i+1][0]+=dp[i][1]+dp[i][2]
    dp[i+1][1]+=dp[i][0]
    dp[i+1][2]+=dp[i][1]

ans=dp[N-1][0]+dp[N-1][1]+dp[N-1][2]
mod=10**9+7
print(ans%mod)