Which of the following given pair is different from rest?

Answer the following questions according to the given statements: There are eight persons M, N, O, P, Q, R, S, and T, who live on four different floors among floor 1, floor 2, floor 3 and floor 4. Each floor has two different flats viz. flat 1 and flat 2. There are 2 flats on each floor flat 1 – flat 2 from left to right in such a way that flat 1 of the fourth floor is exactly above flat 1 of the third floor and flat 1 of the third floor is exactly above flat 1 of the second floor and other flats are situated in the same way. O lives one floor above the floor on which N lives. R lives with N who lives two floors below P. N lives on the second floor. Q lives in flat 2 of the first floor. S lives on the third floor but not in flat 1. T does not live on the fourth floor but in flat 1. N lives in even numbered flat. M and O live in flat 1 but on different floors.