import sys
input = sys.stdin.readline
from collections import defaultdict
 
def compress(l):
    l = list(set(l))
    l.sort()
    idx = defaultdict(int)

    for i in range(len(l)):
        idx[l[i]] = i
    
    return idx, l
    
class BIT:
    def __init__(self, n):
        self.n = n
        self.bit = [0]*(n+1)

    def add(self, i, x):
        i += 1
        
        while i<=self.n:
            self.bit[i] += x
            i += i&(-i)
    
    def get(self, k):
        res = 0
        N = 1
        
        while N<self.n:
            N *= 2
        
        i = N//2
        
        while i>0:
            if res+i<self.n and self.bit[res+i]<k:
                k = k-self.bit[res+i]
                res = res+i
        
            i //= 2
        
        return res
    
Q, K = map(int, input().split())
q = []
l = []

for _ in range(Q):
    inp = list(input().split())
    q.append(inp)
    
    if len(inp)==2:
        l.append(int(inp[1]))

idx, rev_idx = compress(l)
bit = BIT(len(idx.keys()))
cnt = 0

for qi in q:
    if len(qi)==2:
        bit.add(idx[int(qi[1])], 1)
        cnt += 1
    else:
        if cnt>=K:
            i = bit.get(K)
            bit.add(i, -1)
            cnt -= 1
            print(rev_idx[i])
        else:
            print(-1)