<Table> Round 13 . (1 plays 2, 3 plays 14, ...) <Tr> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 5 </Td> <Td> 6 </Td> <Td> 7 </Td> <Td> 8 </Td> </Tr> <Tr> <Td> </Td> <Td> 14 </Td> <Td> 13 </Td> <Td> 12 </Td> <Td> 11 </Td> <Td> 10 </Td> <Td> 9 </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 5 </Td> <Td> 6 </Td> <Td> 7 </Td> <Td> 8 </Td> </Tr> <Tr> <Td> </Td> <Td> 14 </Td> <Td> 13 </Td> <Td> 12 </Td> <Td> 11 </Td> <Td> 10 </Td> <Td> 9 </Td> </Tr> <P> If there are an odd number of competitors, a dummy competitor can be added, whose scheduled opponent in a given round does not play and has a bye . The schedule can therefore be computed as though the dummy were an ordinary player, either fixed or rotating . Instead of rotating one position, any number relatively prime to (n − 1) (\ displaystyle (n - 1)) will generate a complete schedule . The upper and lower rows can indicate home / away in sports, white / black in chess, etc.; to ensure fairness, this must alternate between rounds since competitor 1 is always on the first row . If, say, competitors 3 and 8 were unable to fulfil their fixture in the third round, it would need to be rescheduled outside the other rounds, since both competitors would already be facing other opponents in those rounds . More complex scheduling constraints may require more complex algorithms . This schedule is applied in chess and draughts tournaments of rapid games, where players physically move round a table . In France this is called the Carousel - Berger system (Système Rutch - Berger). </P>

How many games in a group of 4