Now that we know about one-to-one functions, let's talk about onto functions and bijective functions.
A function is onto if and only if each element in the co-domain is the image of, at least, one element in the domain . That is:
If the function is both one-to-one and onto then is a bijection from to or, equivalently, is a bijective function.
In this task, you'll be given an integer and a function where . Determine whether the given function is a bijective function or not.
There are lines in the input.
The first line contains a single positive integer .
The second line contains space separated integers, the values of , respectively.
On a single line, output "YES" if is bijective. Otherwise, output "NO".
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Basically, this is the function .