3 1 person is divided into 15 pairs, and one person directly enters the next round, so 16 people enter the second round.
16 people draw lots and divide them into 8 pairs to select the top eight.
Eight people draw lots, divide them into four pairs and choose the top four.
These four people come to a small circle and play six more games.
1-2 3-4 1-4 2-3 1-3 2-4
It's even smaller to look at them like this.
In short, 3 1 people are busy enough.
Start (a disease)