The first type: 1-8 4-5 2-7 3-6
This is the first round of distribution, and then the winner versus the winner (for example, 1-8 1 win, 4-5, 4 wins, then the second game is 1-4). Loser versus loser (8-5 according to the previous example), the next two games will be the same, then winner versus winner, loser versus loser, and relegation will continue in two games on Friday.
Type 2: 1-7 2-8 3-6 4-5
Unlike the first assignment, the rules are the same.
In any case, the first game is 3-6, 4-5, which is certain.