Artsem has a friend Saunders from University of Chicago. Saunders presented him with the following problem.
Let $[*n*]$ denote the set ${1, ..., *n*}$. We will also write $*f*: [*x*] → [*y*]$ when a function $*f*$ is defined in integer points $1$, ..., $*x*$, and all its values are integers from 1 to $*y*$.
Now then, you are given a function $*f*: [*n*] → [*n*]$. Your task is to find a positive integer $*m*$, and two functions $*g*: [*n*] → [*m*]$, $*h*: [*m*] → [*n*]$, such that $*g*(*h*(*x*)) = *x*$ for all
, and $*h*(*g*(*x*)) = *f*(*x*)$ for all
, or determine that finding these is impossible.
Input
The first line contains an integer $*n*$ ($1 ≤ *n* ≤ 10^{5}$).
The second line contains $*n*$ space-separated integers — values $*f*(1), ..., *f*(*n*)$ ($1 ≤ *f*(*i*) ≤ *n*$).
Output
If there is no answer, print one integer -1.
Otherwise, on the first line print the number $*m*$ ($1 ≤ *m* ≤ 10^{6}$). On the second line print $*n*$ numbers $*g*(1), ..., *g*(*n*)$. On the third line print $*m*$ numbers $*h*(1), ..., *h*(*m*)$.
If there are several correct answers, you may output any of them. It is guaranteed that if a valid answer exists, then there is an answer satisfying the above restrictions.
样例
3
1 2 3
3
1 2 3
1 2 3
3
2 2 2
1
1 1 1
2
2
2 1
-1
题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。