In the first round of the draw, 1 person had a bye, and the rest 16 people played against each other. 8+ 1 = 9 people left.
In the second round of the draw, 1 person took a bye, leaving 8 people to play. 4+ 1 = There are 5 people left.
In the third round of lottery, 1 person bye bye, and the remaining four people will play. 2+ 1 = 3 people left.
In the fourth round, there are only three people left at this time, so there should be no more lottery. Three people play a round robin, that is, every two people play a game, and the third place is decided by points.