You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "how long is a tracking number for ups?" whose answer is 18 characters.
Each document should contain about 30 words, and these documents should contain useful information.

Query: standard length of ups tracking number
Useful Output:

Doc 1: A tracking number or ID is a combination of numbers and possibly letters that uniquely identifies your shipment for national or international tracking.
Doc 2: UPS standard shipping usually takes 1 to 5 business days, depending on the destination. For small businesses and online sellers, this reliable, cost-effective
Doc 3: A UPS SurePost tracking number is a unique 22-character code that provides detailed information about a package's shipping status.
Doc 4: So what do all those numbers (and letters) mean? The most common UPS tracking code format for standard domestic U.S. packages contains 18
Doc 5: Enter one tracking or UPS InfoNotice® number and quickly find out the latest delivery status for your shipment. Quote.