There is a tournament in table tennis (ping-pong) in which 8 players take place.
These are the rules of the tournament:
1 ) Each player plays with every other only 1 game.
2 ) If in the i-th round there is a game between A and B, and a game between C and D, and in the i+1-th round there is a game between A and C, then in the i+1-th there must be a game between B and D.
On how many different ways can we make a schedule for all rounds if it's not important which player plays on which table?