book store awards points based on the following:

A customer purchasing $0$ books earns $0$ points

A customer purchasing $1$ book earns $5$ points

A customer purchasing $2$ books earns $15$ points

A customer purchasing $3$ books earns $30$ points

A customer purchasing $4$ or more books earns $60$ points

Write a program that asks the user to enter a number of books and prints out the points earned