Vampire academy book set of 6

book set of 6. first 3 books are paperback. last 3 are hardback. Teenager Rose Hathaway is a Dhampir -- a human/vampire hybrid. Her best friend is Lissa Dragomir, a princess of the Moroi -- mortal, peaceful vampires. Both teens attend St. Vladamir's Academy, a secret haven for those like them. Rose trains with a handsome mentor to guarantee her place as Lissa's guardian -- although she may have to sacrifice everything to protect Lissa from enemies both within St. Vladamir's walls and outside them.