import collections

de = collections.deque()

f1 = open("output.txt", "w")
with open("input.txt") as f:
	for i in range(1):
		x = f.readline()
	x = int(x)
	q = 0
	for j in range(x):
		q += 1
		for k in range(q):
			a = f.readline().split()
			if a == 1 or a == 2:
				a, b = f.readline().split()
				if a == 1:
					de.appendleft(b)
				elif a == 2:
					de.append(b)
				elif a == 3:
					b = str(b)
					f1.write(b + " ")
					b = int(b)
					de.popleft()
				elif a == 4:
					b = str(b)
					f1.write(b + " ")
					b = int(b)
					de.pop()

f.close()