A software engineer needs to back up 30 files onto external hard drives, each with a capacity of $2.0\text{ MB}$. 5 of the files are $1.2\text{ MB}$ each, 10 of the files are $0.6\text{ MB}$ each, and the rest take up $0.5\text{ MB}$ each. It is not possible to split a file across two different hard drives. What is the smallest number of hard drives needed to store all 30 files?