The table tennis coaching staff will select four players from the right-handed racket player R ,S ,T and the left-handed racket player L, M,N, O to take part in the Olympic Games  At least two right-handed players are required, and all four selected players can play doubles with each other
There are two ways to choose
 It is known that S cannot be paired with L, T cannot be paired with N, and M cannot be paired with L or N