what is the total number of deadline for completion where description is facebook becomes a publicly traded company
{'header': ['Symbol', 'Description', 'Success', 'Date of completion', 'Deadline for completion'], 'page_title': '', 'section_title': '', 'caption': '', 'rows': [['NEWIPOD', 'Apple releases wide-aspect ratio touch screen iPod', 'Yes', 'September 5, 2007', 'September 30, 2007'], ['IPRECAL', 'iPhone recall within the first 3 months of release', 'No', 'September 28, 2007', 'September 28, 2007'], ['DIGGRIP', 'Digg is shut down for posting AACS decryption keys', 'No', 'October 1, 2007', 'October 1, 2007'], ['FACEBOOK', 'Facebook becomes a publicly traded company', 'No', 'October 1, 2007', 'October 1, 2007'], ['RKPLOVR', 'NASA terminates its contract with Rocketplane', 'No', 'October 7, 2007', 'October 7, 2007']]}