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.

**Constraints**

**Input Format**

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.

**Output Format**

On a single line, output "*YES*" if is bijective. Otherwise, output "*NO*".

**Sample Input**

```
3
1 2 3
```

**Sample Output**

```
YES
```

**Explanation**

Basically, this is the function .