78. In a chess tournament, there are an odd number of participants, and each participant plays one game against every other participant. A win earns 1 point, a draw earns 0.5 points, and a loss earns 0 points; it is known that two of the participants scored a total of 8 points, and the average score of the others is an integer. How many participants are there in the tournament?
Reference answer: 9