4. In a chess tournament, every two players play exactly one game against each other. The winner of each game gets 2 points, the loser gets 0 points, and in the case of a draw, both players get 1 point. Now, there are 4 scorers who have tallied the total points of the tournament, but due to some being careless, their data are different, namely 1979, 1980, 1984, 1985. After verification, one of them is correct. The total number of players in this tournament is $\qquad$.