Six pen boxes of different brands, P1, Q2, R3, S4, T5 and U6, are kept one above the other but not necessarily in the same order. P1 is third from the top and immediately below U6. Only two boxes are there between P1 and Q2. There are two boxes between R3 and T5. R3 is placed below T5. How many pen boxes are there between T5 and Q2?