import sys
input = sys.stdin.readline
from heapq import heappop, heappush

def main():
    q, k = map(int, input().split())
    ans = []
    # 下からk個をmax_heap
    small = []
    # それ以外をmin_heap
    large = []
    for i in range(q):
        s = input()
        if len(s) != 2:
            _, v = map(int, s.split())
            # まだk個無い時
            if len(small) < k:
                heappush(small, -v)
            else:
                if -small[0] <= v:
                    heappush(large, v)
                else:
                    a = -heappop(small)
                    heappush(small, -v)
                    heappush(large, a)
        else:
            if len(small) < k:
                ans.append(-1)
#                print(-1)
            else:
                a = -heappop(small)
                ans.append(a)
#                print(a)
                if len(large):
                    b = heappop(large)
                    heappush(small, -b)
    print(*ans, sep="\n")

if __name__ == "__main__":
    main()