Given a subscribed calendar with a url like
https://example.com/example.ics
To force Google Calendar to refresh and reload the contents right now, unsubscribe from the calendar and subscribe to a new calendar with a URL like
https://example.com/example.ics#1
Adding the anchor tag will force Google Calendar to think of it as a new calendar
Take an input string with X opening brackets [ and Y closing brackets ], in a random order.
Determine if the generated string of brackets is balanced, that is it consists of pairs of opening/closing brackets in the correct order with no matched opening and closing pairs.
Do not worry about input other than brackets and empty string.