Broken zoo app

Someone wrote an app to track zoo ticket sales, but didn't finish it. You can try what they made.

Here's the starting screen:

Tickets sellers type in adult and child tickets per transaction. They click the button. It updates the totals.

• There should be at least one adult in each transaction.
• Validate input. It's OK for the child field to be empty.
• Clear the input fields after each transaction.
• There is no localStorage involved.

Fix the app. Upload the URL of your solution.