# No.314 ケンケンパ
def main():
    N = int(input())
    MOD = 10 ** 9 + 7
    # dp[i][j] := count on j-th position doing movement i
    dp = [[0] * N for _ in range(3)]
    dp[0][0] = 1
    for i in range(1, N):
        dp[0][i] = dp[2][i - 1]  # ケン
        dp[1][i] = dp[0][i - 1]  # ケンケン
        dp[2][i] = (dp[0][i - 1] + dp[1][i - 1]) % MOD  # パー
    ans = (dp[0][-1] + dp[1][-1] + dp[2][-1]) % MOD
    print(ans)


if __name__ == "__main__":
    main()