luogu#P3795. 钟氏映射

钟氏映射

Background

In the year 2233, the math teacher and math contest advisor Zhong JG at CSSYZ School is already over 2200 years old. To celebrate the birthday, they gave a problem to the public.

Problem Description

Let N=M={xxN+,xk,kN+}N = M = \left\{x|x\in N_+,x\leq k,k\in N_+\right\}. Let ff be a mapping from NN to MM. Count the number of distinct mappings ff that satisfy f(f(x))=xf(f(x)) = x. Since the answer may be large, output the result modulo 1423333314233333.

Input Format

A single positive integer kk.

Output Format

Output the number of distinct mappings ff satisfying f(f(x))=xf(f(x)) = x, modulo 1423333314233333.

3

4

Hint

For k=3k = 3, the four mappings are:

f(1) f(2) f(3)
1 2 3
3 2
2 1 3
3 2 1

Constraints:

  • For 20% of the testdata, 1k91 \leq k \leq 9.
  • For the other 80% of the testdata, 1k1071 \leq k \leq 10^7.

Memory 20 MB... (I initially set 1 MB and got myself into trouble).

Translated by ChatGPT 5