n=int(input())
mod=10**9+7

dp=[[0]*3 for i in range(n+1)]
dp[0][0]=1
for i in range(1,n+1):
	dp[i][0]=(dp[i-1][1]+dp[i-1][2])%mod
	dp[i][1]=dp[i-1][0]%mod
	dp[i][2]=dp[i-1][1]%mod
print(sum(dp[n])%mod)