n = int(input())
dp = [[0,0,0], [1,0,0], [0,1,0], [1,1,1]] + [[0, 0, 0] for _ in range(n - 3)]
for i in range(4, n + 1):
    for j in range(3):
        a = [0, 1, 2]
        a.pop(j)
        dp[i][j] = sum([dp[i - j - 1][q] for q in a]) % (10 ** 9 + 7)
print(sum(dp[n]))