题目描述
Background

With the arrival of the Dragon Year, Fan Ju also enjoys the Joint Nine Provinces Examination. To excel in the final question, Fan Ju revisits number theory with great enthusiasm.
Number theory leads to prosperous lands!
Problem Description
Fan Ju finds calculating $x^a$ modulo $p$ too simple, so he wants to compute $\sigma_0^s(x^t)$ modulo $p$.
Fan Ju is not satisfied with just one calculation, so he creates an $n \times n$ matrix $A$, ensuring that the element $a_{i,j}$ in the $i$-th row and $j$-th column ($1 \le i, j \le n$) satisfies:
$$ a_{i,j} = \sum_{d \mid \gcd(i,j)} \mu\left(\frac{\gcd(i,j)}{d}\right) \times (\sigma_0(d^s))^t $$
Fan Ju wants to know what this matrix looks like, but it is too large, so please tell him the result of $\det A$ modulo $10^9+7$.
Notes:
- The meanings of various functions in the expression can be found here ($\mu$ represents the Möbius function, $\sigma_0$ represents the divisor count function).
- $\det A$ denotes the determinant of matrix $A$.
Input Format
One line containing three integers $n, s, t$.
Output Format
One line containing an integer representing the answer.
Sample Input and Output
Sample Input #1
2 1 2
Sample Output #1
2
Sample Input #2
2 3 4
Sample Output #2
254
Sample Input #3
19 8 10
Sample Output #3
913255725
Sample Input #4
10000000000 1 2
Sample Output #4
880793261
Notes
Sample 1 Explanation
Matrix $A$ is as follows:
$$ \begin{bmatrix} 1 & 1 \\ 1 & 3 \end{bmatrix} $$
The determinant is $1 \times 3 - 1 \times 1 = 2$.
Sample 2 Explanation
Matrix $A$ is as follows:
$$ \begin{bmatrix} 1 & 1 \\ 1 & 255 \end{bmatrix} $$
The determinant is $1 \times 255 - 1 \times 1 = 254$.
Data Range
This problem uses subtask-based testing.
For $100\%$ of the data, it is guaranteed that $1 \le n \le 10^{11}$, $0 \le s, t < 10^9+7$.
| Subtask Number | $n$ | Special Properties | Score |
|---|---|---|---|
| Subtask #1 | $\le 500$ | None | $8$ |
| Subtask #2 | $\le 10^7$ | $s=1, t=2$ | $5$ |
| Subtask #3 | $\le 10^7$ | $s=1$ | $10$ |
| Subtask #4 | $\le 10^{11}$ | $s=1, t=2$ | $10$ |
| Subtask #5 | $\le 10^{11}$ | $s=1$ | $10$ |
| Subtask #6 | $\le 10^{11}$ | $t=1$ | $2$ |
| Subtask #7 | $\le 10^7$ | $t \le 9$ | $10$ |
| Subtask #8 | $\le 10^{11}$ | $t \le 9$ | $15$ |
| Subtask #9 | $\le 10^7$ | None | $10$ |
| Subtask #10 | $\le 10^{11}$ | None | $20$ |
The Special Properties column is empty if there are no special properties. The values of variables not specified in the subtasks are generated within the range $[0, 10^9+7)$.
Time Limit: $2000$ ms;
Space Limit: $512$ MB.
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分