Greeting by the Clock

Write greeting_for_hour(hour) that takes an hour on a 24-hour clock and returns:

• "Good morning" for hours 5 to 11
• "Good afternoon" for hours 12 to 16
• "Good evening" for hours 17 to 20
• "Good night" for hours 21 to 23 and 0 to 4
• "Invalid hour" if hour is not between 0 and 23

Examples

Input:  hour = 9
Output: "Good morning"

Input:  hour = 17
Output: "Good evening"

Input:  hour = 24
Output: "Invalid hour"

Constraints

• hour is an integer, possibly negative or larger than 23

Goals

• Map ranges of a number onto labels
• Validate input before classifying it
• Handle a range that wraps past midnight