The key is the second round. Since it is a knockout, the number of participating teams must be even, and poker games like the pig association of a certain country are not approved. Then only one of the three losing teams can be selected to enter the second round together (the goal difference is recommended as the competition standard).
It will be easy in the future. In the third round, the two teams drew lots to fight. The two teams that won the championship competed with the two teams that failed for the third place.