Circular Conveyor Buffer Simulation

A parcel-sorting conveyor uses a fixed-capacity circular buffer that behaves as a FIFO queue. The buffer can hold at most C parcels at once. You are given Q operations to apply in order, each one of:

• ENQUEUE x - if the buffer already holds C parcels, print FULL and change nothing; otherwise append parcel value x to the back and print OK.
• DEQUEUE - if the buffer is empty, print EMPTY; otherwise remove the front parcel and print its value.
• FRONT - print the value of the front parcel, or EMPTY if the buffer is empty.
• REAR - print the value of the most recently enqueued parcel still in the buffer, or EMPTY if the buffer is empty.
• SIZE - print the number of parcels currently in the buffer.

Input format

Line 1: two integers C and Q. Next Q lines: one operation each, in one of the forms above.

Output format

Print exactly Q lines: the result of each operation, in order.

Constraints

• 1 <= C <= 100000
• 1 <= Q <= 100000
• For ENQUEUE x: -1000000000 <= x <= 1000000000