title: How to create a user defined countdown timer in Swift?
body: <p>How can I create a user defined countdown timer in Swift?</p>
  
  <p>I got 2 pages in my app. On first page I ask user to write in UITextField a value as hour (for ex: 3), then with segue.identifier, I pass this information to second page, and I want to make a countdown from 3 hours as 02:59:59 format and print it in UILabel. Thanks</p>