Q49

An implementation of a queue $Q$, using two stacks $S1$ and $S2$, is given below: void insert (Q, x) { push (S1, x); } void delete (Q) { if (stack-empty(S2)) then if (stack-empty(S1)) then { print(“Q is empty”); return; } else while (!(stack-empty(S1))){ x=pop(S1); push(S2,x); } x=pop(S2); } Let $n$ insert and $m(\leq n)$ delete operations be performed in an arbitrary order on an empty queue $Q$. Let $x$ and $y$ be the number of push and pop operations performed respectively in the process. Which one of the following is true for all $m$ and $n$?