class Binary_Trie_Vertex:
    def __init__(self):
        self.left = None
        self.right = None
        self.parent = None
        self.size = 0

class Binary_Trie:
    def __init__(self, logn, ismulti = False):
        self.logn = logn
        self.root = Binary_Trie_Vertex()
        self.bi = [1 << i for i in range(logn)]
        self.multi = ismulti
        
    def add(self, x):
        V = self.root
        plus = False
        for i in range(self.logn - 1, -1, -1):
            if x >> i & 1:
                if V.right is None:
                    V.right = Binary_Trie_Vertex()
                    V.right.parent = V
                    plus = True
                V = V.right
                
            else:
                if V.left is None:
                    V.left = Binary_Trie_Vertex()
                    V.left.parent = V
                    plus = True
                V = V.left
        if plus or self.multi:
            while V.parent is not None:
                V.size += 1
                V = V.parent
            V.size += 1

    def remove(self, x):
        V = self.root
        for i in range(self.logn - 1, -1, -1):
            if x >> i & 1:
                if V.right is None:
                    return False
                V = V.right
            else:
                if V.left is None:
                    return False
                V = V.left
        V2 = V
        while V2.parent is not None:
            V2.size -= 1
            V2 = V2.parent
        V2.size -= 1
        while V.size == 0:
            P = V.parent
            if P.right == V:
                P.right = None
            else:
                P.left = None
            if P.right is None and P.left is None:
                pass
            else:
                return True
            V = P
        return True
    
    def search(self, x):
        V = self.root
        for i in range(self.logn - 1, -1, -1):
            if x >> i & 1:
                if V.right is None:
                    return False
                V = V.right
            else:
                if V.left is None:
                    return False
                V = V.left
        return True
    
    def xor_min(self, x):
        xor = 0
        V = self.root
        for i in range(self.logn - 1, -1, -1):
            if x >> i & 1:
                if V.right is not None:
                    V = V.right
                else:
                    xor += self.bi[i]
                    V = V.left
            else:
                if V.left is not None:
                    V = V.left
                else:
                    xor += self.bi[i]
                    V = V.right
        return xor
        
    def __getitem__(self, k):
        return self.Kth_element(k)
    
    def Kth_element(self, k):
        if k < 0:
            k = self.root.size + k
        k += 1
        if k > self.root.size or k <= 0:
            return None
        ret = 0
        V = self.root
        for i in range(self.logn - 1, -1, -1):
            if V.left is None:
                ret += self.bi[i]
                V = V.right
            elif V.right is None:
                V = V.left
            elif V.left.size >= k:
                V = V.left
            else:
                ret += self.bi[i]
                k -= V.left.size
                V = V.right
        return ret

Q, k = map(int, input().split())
bt = Binary_Trie(60, True)

for _ in range(Q):
    query = list(map(int, input().split()))
    if query[0] == 1:
        bt.add(query[1])
    else:
        ans = bt[k - 1]
        if ans is None:
            print(-1)
        else:
            print(ans)
            bt.remove(ans)