Read in a time such as 3 pm and print the equivalent military hour (such as 15). Validate the input.
If the input doesn't start with an integer, print: Error: Not an integer.
If the number isn't between 1 and 12, print: Error: The hour must be between 1 and 12.
If the suffix isn't "am" or "pm", print: Error: The suffix must be am or pm.