# Smallest missing number in array

## Question

Write a function that outputs the smallest missing number in a sorted array of n unique integers. The integers in the array range from `0`

to `m-1`

, where `m > n`

.

The function should be called `0`

SmallestMissingNumber` and the 3 inputs are:

- the array
- the "start value" of the array
- the length of the array - 1

**For example:**

```
#Input:
[0, 1, 3, 4, 8, 9], n = 5, m = 10
#Output:
2
#Input:
[4, 7, 9, 11], n = 4, m = 12
#Output:
0
```