N = int(input())
MOD = 10**9+7
dp = [[0 for j in range(4)] for i in range(N+1)]
dp[0][0] = 1
for i in range(N):
	for j in range(4):
		for k in range(1,4):
			if j == k:
				continue
			if i+k <= N:
				dp[i+k][k] += dp[i][j] % MOD
print(sum(dp[N]) % MOD)