Implement a custom Apex class that simulates a queue (First-In, First-Out) using two stacks (Last-In, First-Out). Your implementation should include enqueue and dequeue methods.

Methods to Implement

• enqueue(Integer value): Adds an element to the back of the queue.
• dequeue(): Removes and returns the element at the front of the queue.

Examples:

MyQueue q = new MyQueue();
q.enqueue(1);
q.enqueue(2);
System.assertEquals(1, q.dequeue()); // returns 1
q.enqueue(3);
System.assertEquals(2, q.dequeue()); // returns 2
System.assertEquals(3, q.dequeue()); // returns 3