Hi Excel Gurus !

I am in need of a macro / formula which is able to find the missing date range(s).
Example:
John stayed in Apartment A&B for period : 1 February until 15 September.

Rental paid shown in records :
Apartment A rental period : 1 January until 28 February
Apartment B rental period : 1 April until 31 July
Apartment A rental again : 1 June until 31 August (overlaps)

The above start date - end date is keyed into cell A1:B3.

I need excel to show results :
1 March - 31 March
1 September - 15 September
which represent periods where no rental paid was shown in records.

My thousand thanks! in advance for any help on this.
SauQ