1 round, A and B, the winner is F 1, and the loser is F2;
In the second round, the loser F2 of 1 round played against C. The winner was S 1 and the loser was the third.
In the third round, the winner of 1 round F 1 competed with the winner of the second round S 1. The winner is 1 and the loser is second.