N = int(raw_input())
MOD = 1000000000 + 7
dp = [[0 for i in range(3)] for i in range(N + 1)]
dp[0][0] = 1
for i in range(1,N + 1):
	dp[i][1] = (dp[i][1] + dp[i - 1][0]) % MOD
	dp[i][2] = (dp[i][2] + dp[i - 1][1]) % MOD
	dp[i][0] = (dp[i][0] + dp[i - 1][1]) % MOD
	dp[i][0] = (dp[i][0] + dp[i - 1][2]) % MOD
ans = 0
for i in range(3):
	ans = (ans + dp[N][i]) % MOD
print ans