N = int(input())
MOD = 10**9+7
dp = [[-1 for j in range(4)] for i in range(N)]
def dfs(n,pre):
	if n == N:
		return 1
	if dp[n][pre] != -1:
		return dp[n][pre]
	ret = 0
	for i in range(1,4):
		if pre == i:
			continue
		if n+i <= N:
			ret += dfs(n+i,i)
	dp[n][pre] = ret % MOD
	return dp[n][pre]
print(dfs(0,0))