import sys
from collections import deque
input = sys.stdin.readline
N = int(input())
queue = deque([])
while True:
a = int(input())
if a == -1:
break
if a == 0 and len(queue) != 0:
queue.popleft()
elif a!=0 and len(queue) != N:
queue.append(a)
if len(queue) == 0:
print("empty")
else:
print(*queue)