Question 24
In a math competition, 3 problems are proposed, each of which is evaluated with a full score between 0 and 7 (extremes included). It is known that, however two competitors are chosen, there is at most a problem on which they have obtained the same score (for example, there are no two competitors whose scores on the three problems are 7, 1, 2 for the first and 7, 5, 2 for the second, but there could be be two competitors whose scores are 7, 1, 2 and 7, 2, 1). How many are the participants in the race at most?