CF285D.Permutation Sum
普及/提高-
通过率:0%
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题目描述
Permutation p is an ordered set of integers p1,p2,...,pn , consisting of n distinct positive integers, each of them doesn't exceed n . We'll denote the i -th element of permutation p as pi . We'll call number n the size or the length of permutation p1,p2,...,pn .
Petya decided to introduce the sum operation on the set of permutations of length n . Let's assume that we are given two permutations of length n : a1,a2,...,an and b1,b2,...,bn . Petya calls the sum of permutations a and b such permutation c of length n , where ci=((ai−1+bi−1) mod n)+1 (1<=i<=n) .
Operation means taking the remainder after dividing number x by number y .
Obviously, not for all permutations a and b exists permutation c that is sum of a and b . That's why Petya got sad and asked you to do the following: given n , count the number of such pairs of permutations a and b of length n , that exists permutation c that is sum of a and b . The pair of permutations x,y (x=y) and the pair of permutations y,x are considered distinct pairs.
As the answer can be rather large, print the remainder after dividing it by 1000000007 ( 109+7 ).
输入格式
The single line contains integer n (1<=n<=16) .
输出格式
In the single line print a single non-negative integer — the number of such pairs of permutations a and b , that exists permutation c that is sum of a and b , modulo 1000000007 ( 109+7 ).
输入输出样例
输入#1
3
输出#1
18
输入#2
5
输出#2
1800