How many different set of candidates were there when the incumbent was david e. finley?
{'header': ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates'], 'page_title': 'United States House of Representatives elections, 1916', 'section_title': 'South Carolina', 'caption': 'South Carolina', 'rows': [['South Carolina 1', 'Richard S. Whaley', 'Democratic', '1913 (special)', 'Re-elected', 'Richard S. Whaley (D) 95.4% J. O. Ladd (R) 4.6%'], ['South Carolina 2', 'James F. Byrnes', 'Democratic', '1910', 'Re-elected', 'James F. Byrnes (D) 98.5% Isaac Myers (R) 1.5%'], ['South Carolina 3', 'Wyatt Aiken', 'Democratic', '1902', 'Lost primary Democratic hold', 'Frederick H. Dominick (D) 100%'], ['South Carolina 4', 'Samuel J. Nicholls', 'Democratic', '1915 (special)', 'Re-elected', 'Samuel J. Nicholls (D) 99.4% G. F. Mills (R) 0.6%'], ['South Carolina 5', 'David E. Finley', 'Democratic', '1898', 'Re-elected', 'David E. Finley (D) 100%']]}