## Letter Space Number
### Instructions
Create a function named `letterSpaceNumber` that accepts a string; returning an array with every instance of a letter, followed by a space, followed by a number, only if that number has only one digit, and is not followed by any letter.
### Examples
```js
console.log(letterSpaceNumber('example 1, example 20'))
// output: ['e 1']
```
### Notions
- [RegEx Shorthand Character Sets](https://github.com/ziishaned/learn-regex#3-shorthand-character-sets)
