Day 350

Good morning! Here's your coding interview problem for today.

This problem was asked by Uber.

Write a program that determines the smallest number of perfect squares that sum up to `N`.

Here are a few examples:
```
Given N = 4, return 1 (4)
Given N = 17, return 2 (16 + 1)
Given N = 18, return 2 (9 + 9)
```