The table tennis coaching team will select four players from the right-handed players R, S, T and left-handed players L, M, N, O to participate in the Olympic Games. At least two right-handed players are required to participate And the four players selected can be paired with each other for doubles. 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. If R is not selected in the eight teams, how many different selection methods are there? ['Only one.', 'Two.', 'Three.', 'Four types.']