Group a, group b, five teams each;
Group C, Group D and Group E each have four teams.
The first stage of a preliminary single cycle. Select the top two to enter the second stage.
The second stage rematch single cycle. Draw lots to decide, divide into two groups, each group has five teams, and select the top two to enter the third stage.
The third stage final knockout. In the second stage, one group fights first, and the other group fights later. The winner plays the champion and runner-up, and the loser plays three or four finals.