from heapq import heappush, heappop
import sys
def input():
	return sys.stdin.buffer.readline()[:-1]

n, k = map(int, input().split())
q1, q2 = [], []

def add(x):
	heappush(q1, -x)
	if len(q1) > k:
		tmp = heappop(q1)
		heappush(q2, -tmp)
	return

def remove():
	if len(q1) < k:
		return -1
	else:
		res = heappop(q1)
		if q2:
			nxt = heappop(q2)
			heappush(q1, -nxt)
		return -res

for _ in range(n):
	t = input().split()
	if len(t) == 2:
		add(int(t[1]))
	else:
		print(remove())