4
M, N, O, P, Q and R live on six different floors of the same building. The lowermost floor in the building is numbered 1, the floor above it, number 2 and so on till the topmost floor is numbered 6. Q lives on an odd-numbered floor but not on the lowermost floor. Only one person lives between Q and N. R lives immediately above Q. Only two people live between O and Q. If P lives immediately above R, where does M live?