#D2961. Cyclic Permutations
Cyclic Permutations
Cyclic Permutations
A permutation of length n is an array consisting of n distinct integers from 1 to n in arbitrary order. For example, [2,3,1,5,4] is a permutation, but [1,2,2] is not a permutation (2 appears twice in the array) and [1,3,4] is also not a permutation (n=3 but there is 4 in the array).
Consider a permutation p of length n, we build a graph of size n using it as follows:
- For every 1 ≤ i ≤ n, find the largest j such that 1 ≤ j < i and p_j > p_i, and add an undirected edge between node i and node j
- For every 1 ≤ i ≤ n, find the smallest j such that i < j ≤ n and p_j > p_i, and add an undirected edge between node i and node j
In cases where no such j exists, we make no edges. Also, note that we make edges between the corresponding indices, not the values at those indices.
For clarity, consider as an example n = 4, and p = [3,1,4,2]; here, the edges of the graph are (1,3),(2,1),(2,3),(4,3).
A permutation p is cyclic if the graph built using p has at least one simple cycle.
Given n, find the number of cyclic permutations of length n. Since the number may be very large, output it modulo 10^9+7.
Please refer to the Notes section for the formal definition of a simple cycle
Input
The first and only line contains a single integer n (3 ≤ n ≤ 10^6).
Output
Output a single integer 0 ≤ x < 10^9+7, the number of cyclic permutations of length n modulo 10^9+7.
Examples
Input
4
Output
16
Input
583291
Output
135712853
Note
There are 16 cyclic permutations for n = 4. [4,2,1,3] is one such permutation, having a cycle of length four: 4 → 3 → 2 → 1 → 4.
Nodes v_1, v_2, …, v_k form a simple cycle if the following conditions hold:
- k ≥ 3.
- v_i ≠ v_j for any pair of indices i and j. (1 ≤ i < j ≤ k)
- v_i and v_{i+1} share an edge for all i (1 ≤ i < k), and v_1 and v_k share an edge.
inputFormat
outputFormat
output it modulo 10^9+7.
Please refer to the Notes section for the formal definition of a simple cycle
Input
The first and only line contains a single integer n (3 ≤ n ≤ 10^6).
Output
Output a single integer 0 ≤ x < 10^9+7, the number of cyclic permutations of length n modulo 10^9+7.
Examples
Input
4
Output
16
Input
583291
Output
135712853
Note
There are 16 cyclic permutations for n = 4. [4,2,1,3] is one such permutation, having a cycle of length four: 4 → 3 → 2 → 1 → 4.
Nodes v_1, v_2, …, v_k form a simple cycle if the following conditions hold:
- k ≥ 3.
- v_i ≠ v_j for any pair of indices i and j. (1 ≤ i < j ≤ k)
- v_i and v_{i+1} share an edge for all i (1 ≤ i < k), and v_1 and v_k share an edge.
样例
4
16
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