P23333 [AtCoder] Dice Product 3
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题目描述

Problem Statement

You have an integer 1 and a die that shows integers between 1 and 6 (inclusive) with equal probability.
You repeat the following operation while your integer is strictly less than N:

  • Cast a die. If it shows x, multiply your integer by x.

Find the probability, modulo 998244353, that your integer ends up being N.

How to find a probability modulo 998244353?
We can prove that the sought probability is always rational.
Additionally, under the constraints of this problem, when that value is represented as $\frac{P}{Q}$ with two coprime integers P and Q, we can prove that there is a unique integer R such that $R \times Q \equiv P\pmod{998244353}$ and $0 \leq R \lt 998244353.$ Find this R.

Input

The input is given from Standard Input in the following format:
N

Output

Print the probability, modulo 998244353, that your integer ends up being N.

Constraints

  • $2 \leq N \leq 10^{18}$
  • N is an integer.

Sample Input 1

6

Sample Output 1

239578645

One of the possible procedures is as follows.

  • Initially, your integer is 1.
  • You cast a die, and it shows $2. Your integer becomes 1 \times 2 = 2$.
  • You cast a die, and it shows $4. Your integer becomes 2 \times 4 = 8$.
  • Now your integer is not less than 6, so you terminate the procedure.

Your integer ends up being 8, which is not equal to N = 6.
The probability that your integer ends up being 6 is $\frac{7}{25}. Since 239578645 \times 25 \equiv 7 \pmod{998244353}$, print 239578645.

Sample Input 2

7

Sample Output 2

0

No matter what the die shows, your integer never ends up being 7.

Sample Input 3

300

Sample Output 3

183676961

Sample Input 4

979552051200000000

Sample Output 4

812376310

输入格式

见题面 Input 部分

输出格式

见题面 Output 部分

样例输入
6
样例输出
239578645