#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define per(i,n) for(ll i=(n)-1;i>=0;i--)
#define perl(i,r,l) for(ll i=r-1;i>=l;i--)
#define fi first
#define se second
#define pb push_back
#define ins insert
#define pqueue(x) priority_queue<x,vector<x>,greater<x>>
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
#define rev(x) reverse(x);
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using pl=pair<ll,ll>;
using vpl=vector<pl>;
using vvpl=vector<vpl>;
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=2e9+1;
const ll INF=4e18;
const ll dy[8]={-1,0,1,0,1,1,-1,-1};
const ll dx[8]={0,-1,0,1,1,-1,1,-1};
template <typename T> inline bool chmax(T &a, T b) {
  return ((a < b) ? (a = b, true) : (false));
}
template <typename T> inline bool chmin(T &a, T b) {
  return ((a > b) ? (a = b, true) : (false));
}
template<typename U = unsigned, int B = 32>
class binary_trie {
    struct node {
        int cnt;
        node *ch[2];
        node() : cnt(0), ch{ nullptr, nullptr } {}
    };
    node* add(node* t, U val, int b = B - 1) {
        if (!t) t = new node;
        t->cnt += 1;
        if (b < 0) return t;
        bool f = (val >> (U)b) & (U)1;
        t->ch[f] = add(t->ch[f], val, b - 1);
        return t;
    }
    node* sub(node* t, U val, int b = B - 1) {
        assert(t);
        t->cnt -= 1;
        if (t->cnt == 0) return nullptr;
        if (b < 0) return t;
        bool f = (val >> (U)b) & (U)1;
        t->ch[f] = sub(t->ch[f], val, b - 1);
        return t;
    }
    U get_min(node* t, U val, int b = B - 1) const {
        assert(t);
        if (b < 0) return 0;
        bool f = (val >> (U)b) & (U)1; f ^= !t->ch[f];
        return get_min(t->ch[f], val, b - 1) | ((U)f << (U)b);
    }
    U get(node* t, int k, int b = B - 1) const {
        if (b < 0) return 0;
        int m = t->ch[0] ? t->ch[0]->cnt : 0;
        return k < m ? get(t->ch[0], k, b - 1) : get(t->ch[1], k - m, b - 1) | ((U)1 << (U)b);
    }
    int count_lower(node* t, U val, int b = B - 1) {
        if (!t || b < 0) return 0;
        bool f = (val >> (U)b) & (U)1;
        return (f && t->ch[0] ? t->ch[0]->cnt : 0) + count_lower(t->ch[f], val, b - 1);
    }
    node *root;
public:
    binary_trie() : root(nullptr) {}
    int size() const {
        return root ? root->cnt : 0;
    }
    bool empty() const {
        return !root;
    }
    void insert(U val) {
        root = add(root, val);
    }
    void erase(U val) {
        root = sub(root, val);
    }
    U max_element(U bias = 0) const {
        return get_min(root, ~bias);
    }
    U min_element(U bias = 0) const {
        return get_min(root, bias);
    }
    int lower_bound(U val) { // return id
        return count_lower(root, val);
    }
    int upper_bound(U val) { // return id
        return count_lower(root, val + 1);
    }
    U operator[](int k) const {
        assert(0 <= k && k < size());
        return get(root, k);
    }
    int count(U val) const {
        if (!root) return 0;
        node *t = root;
        for (int i = B - 1; i >= 0; i--) {
            t = t->ch[(val >> (U)i) & (U)1];
            if (!t) return 0;
        }
        return t->cnt;
    }
};

int main(){
  ll q,k;cin >> q >> k;
  binary_trie<ll,62> bt;
  while(q--){
    ll t;cin >> t;
    if(t==1){
      ll x;cin >> x;
      bt.insert(x);
    }
    else{
      ll p=bt.size();
      if(p<k)cout << -1 << endl;
      else{
        ll ans=bt[k-1];
        cout << ans << endl;
        bt.erase(ans);
      }
    }
  }
}