def print_func(data):
    if data:
        for car in parking_cars:
            print(car)
    else:
        print(f"Parking Lot is Empty")

n = int(input())

parking_cars = set()

for _ in range(n):
    information = input()
    information_split = information.split(", ")
    direction = information_split[0]
    plate_number = information_split[1]
    
    if direction == "IN":
        parking_cars.add(plate_number)
    
    elif direction == "OUT":
        parking_cars.remove(plate_number)
        
print_func(parking_cars)