# Queue

The Queue is one of the core data structures in many algorithms. Itβs very similar to a real-life queue. The first element added to a queue will be the first to be βservedβ and removed from it.
Imagine a line of ants standing in a queue waiting for a coffee. The first ant in the queue will get coffee and leave the queue, then the next ant will get a coffee and leave the queue, and this process will continue until the queue is empty and there are no ants waiting for a coffee.
Declaring and using a queue is made straightforward in most languages - as most general-purpose languages (like Python, C++, Java, etc.) have implemented the queue data structure for easier use. We can still implement the queue ourselves using a linked list. Can you think of how to do that π€?
``````from queue import Queue

q = Queue()    # Create a new queue
q.put(1)       # Add 1 to the front of the queue
q.put(3)       # Add 3 after 2

# Remove elements from the queue using get()
print(q.get()) # prints 1
print(q.get()) # prints 2
print(q.get()) # prints 3``````

### Challenge: Queue Simulation

You are implementing a system that should keep track of the customers in the store. There are two things that your system should be capable of - it should be able to add a customer to the waiting line, and it should be able to remove the first customer from the waiting line when they are satisfied. Each time you remove a customer, you should print their name.

#### Input

The first line of the input contains a single integer `n` (1 β€ n β€ 100 000).
The next `n` lines contain the operations - either `add` or `pop`:
• `add` operation is followed by a name, where you should add the customer to the waiting line.
• `pop` operation only contains the operation name and nothing else.
Itβs guaranteed that thereβs always someone in the line before a `pop` operation, so the operations are valid.
The names are guaranteed to not exceed 20 symbols.

#### Output

For each `pop` operation, the program should print the name of the customer at the front of the line.