# ... (previous code)

def dispense_item(counter, item_name, gate_duration, buzzer_freq, buzzer_duration):
    if counter > 0:
        try:
            # Check if the input is a valid number
            number = int(c)
            
            # Dispensing logic
            print(f"\nYOU HAVE ORDERED {item_name}!")
            print(f"PLEASE WAIT {gate_duration} SECONDS\n")
            
            for _ in range(1):
                sleep(0.5)
                gate.move(90)
                sleep(0.5)
                gate.move(0)
                sleep(gate_duration)
                buzzer.init(freq=buzzer_freq, duty=1023)
                sleep(0.5)
                buzzer.init(freq=1, duty=10)
                sleep(0.5)
                gate.move(90)
                sleep(1)

            print(f"{item_name} READY!")
            print(f"HERE IS YOUR {item_name}")
            print("THANK YOU AND COME AGAIN!\n")
            counter -= 1

        except ValueError:
            print("Invalid input. Please enter a number.")
    else:
        print(f"{item_name} IS UNAVAILABLE!")
        print("PLEASE ORDER SOMETHING ELSE\n")

    return counter

while True:  # to endless repeating
    # ... (previous code)

    c = input("\nEnter a value: ")

    if c == "1":
        counter10 = dispense_item(counter10, "NASI LEMAK", 5, 1000, 0.5)

    if c == "2":
        counter20 = dispense_item(counter20, "KUEY TEOW GORENG", 5, 1000, 0.5)

    if c == "3":
        counter30 = dispense_item(counter30, "CENDOL", 5, 1000, 0.5)

    if c == "4":
        counter40 = dispense_item(counter40, "ICED TEH TARIK", 3, 1000, 0.5)

    # ... (remaining code)