import sys
input = sys.stdin.readline

class BIT:
    def __init__(self, n):
        self.n = n
        self.data = [0] * (n + 1)

    def ope(self, x, y):
        return x + y

    def update(self, i, v):
        while i <= self.n:
            self.data[i] = self.ope(self.data[i], v)
            i += i & -i

    def query(self, i):
        ret = 0
        while 0 < i:
            ret = self.ope(self.data[i], ret)
            i &= i - 1
        return ret

    def lowerBound(self, w):
        if w <= 0: return 0
        x, k = 0, 2**self.n.bit_length()
        while k:
            if x+k <= self.n and self.data[x+k] < w:
                w -= self.data[x+k]
                x += k
            k >>= 1
        return x + 1

def main():
    q, k = map(int, input().split())
    vs = set()
    query = []
    for i in range(q):
        s = input()
        if len(s) != 2:
            _, v = map(int, s.split())
            vs.add(v)
            query.append(v)
        else:
            query.append(-1)
    # 座圧, 1-indexed
    d = {}
    dd = {}
    for i, j in enumerate(sorted(list(vs))):
        d[j] = i+1
        dd[i+1] = j
    # BIT
    n = len(d)
    B = BIT(n)
    for q in query:
        if q >= 0:
            p = d[q]
            B.update(p, 1)
        else:
            if B.query(n) >= k:
                a = B.lowerBound(k)
                print(dd[a])
                B.update(a, -1)
            else:
                print(-1)

if __name__ == "__main__":
    main()