Implementing a Linked List Based Queue

Implement a queue using a linked list. The queue supports two operations: enqueue(x) which adds an element \( x \) to the rear, and dequeue() which removes and returns the element at the front. If the queue is empty, the dequeue() operation should return \( -1 \).

Formally, if we denote the queue by \( \text{MyQueue} \), then the operations are defined as follows:

\( \text{enqueue}(x): \) Add element \( x \) to the rear of the queue.
\( \text{dequeue}(): \) Remove and return the front element of the queue; if the queue is empty, return \( -1 \).</p>

inputFormat

The first line contains an integer \( n \) representing the number of operations.

Each of the next \( n \) lines contains an operation in one of the following forms:

• enqueue x — insert the integer \( x \) into the queue.
• dequeue — remove the front element of the queue and print its value. If the queue is empty, print \( -1 \).

outputFormat

For each dequeue operation, output the returned value on a separate line.

## sample

5
enqueue 1
enqueue 2
dequeue
enqueue 3
dequeue

1
2

</p>