How many persons are there between A and F?

Study the following information carefully and answer the question given below: There are eight people A, B, Y, Z, M, N, E and F are living in a 8 floor Building on different floors from top to bottom (such as ground floor is numbered as 1 and top floor is numbered as 8) but not necessarily in the same order. M lives immediately above the floor on which Y lives but not on an even numbered floor. Z lives on the floor which is a prime number but not on the 3rd floor. N lives immediately below the floor on which B lives. The person lives between A and Y is not more than three and not less than two. A live on the topmost floor. There is one person living between the floors on which F and Z lives. F lives immediately above the floor on which B lives.