n=int(input())
dp=[[0,0,0] for i in range(n)]
dp[0][1]=1
for i in range(n-1):
    if dp[i][0]!=0:
        dp[i+1][1]+=dp[i][0]
    if dp[i][1]!=0:
        dp[i+1][0]+=dp[i][1]
        dp[i+1][2]+=dp[i][1]
    if dp[i][2]!=0:
        dp[i+1][0]+=dp[i][2]
print(sum(dp[n-1])%(10**9+7))