Seven dance students - T, U, V, W, X, Y and Z - are to give a performance, and the judges have to decide the sequence in which they will perform. Each student will perform exactly one item, a solo ballet. In deciding the order of performance, the instructor must observe the following restrictions:

1. X cannot perform first or second.

2. W cannot perform until Z has performed.

3. Neither T nor Y can perform seventh.

4. Either Y or Z must perform immediately after W.

5. V. must perform either immediately after or immediately before U.

If U performs third, what is the latest position in which Y can perform ?