def main():
    MOD = 10**9+7
    N = int(input())

    if N <= 2:
        exit(print(1))

    dp = [[0] * (3) for _ in range(N + 1)]
    dp[1][0] = 1
    dp[2][1] = 1
    dp[3][2] = 1

    for i in range(1, N):
        for j in range(3):
            dp[i][j] %= MOD
            for k in range(3):
                if k == j:
                    continue
                # dp[i][j] から k+1歩進む
                if i + k + 1 <= N:
                    dp[i + (k + 1)][k] += dp[i][j]

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

if __name__ == "__main__":
    main()