Type: RemoteJudge 3000ms 512MiB

A Random Code Problem

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Description

You are given an integer array $a_0, a_1, \dots, a_{n - 1}$, and an integer $k$. You perform the following code with it:

long long ans = 0; // create a 64-bit signed variable which is initially equal to 0
for(int i = 1; i <= k; i++)
{
int idx = rnd.next(0, n - 1); // generate a random integer between 0 and n - 1, both inclusive
// each integer from 0 to n - 1 has the same probability of being chosen
ans += a[idx];
a[idx] -= (a[idx] % i);
}

Your task is to calculate the expected value of the variable ans after performing this code.

Note that the input is generated according to special rules (see the input format section).

The only line contains six integers $n$, $a_0$, $x$, $y$, $k$ and $M$ ($1 \le n \le 10^7$; $1 \le a_0, x, y < M \le 998244353$; $1 \le k \le 17$).

The array $a$ in the input is constructed as follows:

  • $a_0$ is given in the input;
  • for every $i$ from $1$ to $n - 1$, the value of $a_i$ can be calculated as $a_i = (a_{i - 1} \cdot x + y) \bmod M$.

Let the expected value of the variable ans after performing the code be $E$. It can be shown that $E \cdot n^k$ is an integer. You have to output this integer modulo $998244353$.

Input

The only line contains six integers $n$, $a_0$, $x$, $y$, $k$ and $M$ ($1 \le n \le 10^7$; $1 \le a_0, x, y < M \le 998244353$; $1 \le k \le 17$).

The array $a$ in the input is constructed as follows:

  • $a_0$ is given in the input;
  • for every $i$ from $1$ to $n - 1$, the value of $a_i$ can be calculated as $a_i = (a_{i - 1} \cdot x + y) \bmod M$.

Output

Let the expected value of the variable ans after performing the code be $E$. It can be shown that $E \cdot n^k$ is an integer. You have to output this integer modulo $998244353$.

3 10 3 5 13 88
2 15363 270880 34698 17 2357023
382842030
319392398

Note

The array in the first example test is $[10, 35, 22]$. In the second example, it is $[15363, 1418543]$.

20240118期望的线性选讲

Not Attended
Status
Done
Rule
ACM/ICPC
Problem
12
Start at
2024-1-18 8:00
End at
2024-1-23 8:00
Duration
120 hour(s)
Host
Partic.
19