# Find n-th missing element in unsorted array

## Question

Suppose you're given an unsorted array, `a`

. The array is intended to have all integer elements between its minimum and maximum, but could be missing some elements. Write a python function to find the `n-th`

missing element in the array.

Consider the array in sorted order, then find the `n-th`

missing number. If the `n-th`

missing number does not exist, you can output `'Does not exist'`

.

Examples:

```
Input: a = [2, 3, 11, 9], n = 3
Output: 6
```

Missing elements in array: [4, 5, 6, 7, 8, 10]. So, the 3rd missing element is 6.

```
Input: a = [2, 3, 5], n = 5
Output: 'Does not exist'
```

Since there is no 5th missing element in the array, we output 'Does not exist' (the only missing element here is 4).