MOD = 10**9+7
N = int(input())
DP = [[0] * (3) for _ in range(N + 1)]
DP[0][0] = 1
for i in range(N):
    for j in range(3):
        DP[i][j] %= MOD
        DP[i + 1][(j + 1)%3] += DP[i][j]
        if j == 1:
            DP[i + 1][0] += DP[i][j]

ans = sum(DP[-1])
ans %= MOD
print(ans)