Consider a sequence $a$ of elements $a_0 = 1$, $a_1 = 5$, $a_2 = 7$, $a_3 = 8$, $a_4 = 9$, and $a_5 = 2$. The following operations are performed on a stack $S$ and a queue $Q$, both of which are initially empty. I: push the elements of $a$ from $a_0$ to $a_5$ in that order into $S$. II: enqueue the elements of $a$ from $a_0$ to $a_5$ in that order into $Q$. III: pop an element from $S$. IV: dequeue an element from $Q$. V: pop an element from $S$. VI: dequeue an element from $Q$. VII: dequeue an element from $Q$ and push the same element into $S$. VIII: Repeat operation VII three times. IX: pop an element from $S$. X: pop an element from $S$. The top element of $S$ after executing the above operations is ____________.

Consider a sequence a of elements a0 = 1, a1 = 5, a2 = 7, a3 = 8, a4 = 9, and a5 = 2. The following operations are performed on a stack S and a queue Q, both of which are initially empty. I: push the elements of a from a0 to a5 in that order into S. II: enqueue the elements of a from a0 to a5 in that order into Q. III: pop an element from S. IV: dequeue an element from Q. V: pop an element from S. VI: dequeue an element from Q. VII: dequeue an element from Q and push the same element into S. VIII: Repeat operation VII three times. IX: pop an element from S. X: pop an element from S. The top element of S after executing the above operations is …

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