Eight books were picked from a huge library and are arranged in two parallel rows containing four books each. The books are Adventures of Tom Sawyer, A Brief History of Time, Robinson Crusoe, The Bell Jar, The Odyssey, On the Origin of Species, The Alchemist, and Matilda . A Brief History of Time, The Bell Jar, On the Origin of Species, and Matilda are kept in the first row, facing North and Adventures of Tom Sawyer, Robinson Crusoe, The Odyssey, and The Alchemist are placed in the second row facing South . Thus, each book in the first row faces another book placed in the second row. Each of the books is from different floors of the library. i. e. floor 1 to 8. A Brief History of Time is from the fourth floor and the book from the first floor is not kept next to The Alchemist in the row. Matilda is kept opposite to the book which is kept to the immediate right of the book from the second floor of the library. The book from the third floor is kept exactly between The Bell Jar and the book from the eighth floor. The Alchemist is from a floor that is even a prime number. Robinson Crusoe is neither from the first floor nor the fifth floor. The Alchemist is placed opposite to On the Origin of Species, which is from the eighth floor. The Odyssey is kept between Adventures of Tom Sawyer and The Alchemist. The Bell Jar is kept at the left end of the row and it is from the sixth floor.
How many books floors are between the floors in which Roinson Crusoe and Matilda are kept?​