from functools import lru_cache


def main():
    K = int(input())

    @lru_cache
    def expect_dice_sum_K(now: int) -> int:
        if now >= K:
            return 0
        return sum(expect_dice_sum_K(now+next_) for next_ in range(1, 7))/6 + 1

    print(expect_dice_sum_K(0))


if __name__ == "__main__":
    main()