#include <bits/stdc++.h>
#define int long long

using namespace std;
const int maxn = 1 << 20;

struct node {
  int mn = INT_MAX;
  int imn = -1;
  static node combine(node a, node b) {
    node c;
    if (a.mn < b.mn) {
      c.mn = a.mn;
      c.imn = a.imn;
    } else {
      c.mn = b.mn;
      c.imn = b.imn;
    }
    return c;
  }
};

struct segtree {
  vector<node> tree;
  segtree() {
    tree.resize(maxn * 2 - 1);
  }
  void build(int x, int l, int r, const vector<int>& a, int ch) {
    if (l == r) {
      if (l < a.size() && l % 2 == ch) {
        tree[x].mn = a[l];
        tree[x].imn = l;
      }
      return;
    }
    int mid = (l + r) >> 1;
    build(2 * x + 1, l, mid, a, ch);
    build(2 * x + 2, mid + 1, r, a, ch);
    tree[x] = node::combine(tree[2 * x + 1], tree[2 * x + 2]);
  }
  node get(int x, int l, int r, int ll, int rr) {
    if (r < ll || rr < l)
      return {};
    if (ll <= l && r <= rr)
      return tree[x];
    int mid = (l + r) >> 1;
    return node::combine(get(2 * x + 1, l, mid, ll, rr),
                         get(2 * x + 2, mid + 1, r, ll, rr));
  }
};

vector<segtree> sg(2);
vector<pair<int, int>> val;
vector<vector<int>> rg;
vector<int> deg;

int c = -1;
void rec(int l, int r, int p) {
  if (l > r)
    return;
  auto [aL, L] = sg[l % 2].get(0, 0, maxn - 1, l, r);
  auto [aR, R] = sg[r % 2].get(0, 0, maxn - 1, L, r);
  c += 1;
  val[c] = {aL, aR};
  if (p != -1) {
    rg[p].push_back(c);
    deg[c] += 1;
  }
  rec(L + 1, R - 1, c);
  rec(l, L - 1, p);
  rec(R + 1, r, p);
}

signed main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
#ifdef LOCAL
  freopen("input", "r", stdin);
#endif
  int n, k;
  cin >> n >> k;
  rg.resize(n / 2);
  deg.resize(n / 2);
  val.resize(n / 2);
  vector<int> a(n);
  for (auto& i : a)
    cin >> i;
  for (int i = 0; i < 2; i++)
    sg[i].build(0, 0, maxn - 1, a, i);
  rec(0, n - 1, -1);
  deque<int> ans;
  set<pair<pair<int, int>, int>> q;
  for (int i = 0; i < n / 2; i++)
    if (deg[i] == 0)
      q.emplace(val[i], i);
  while (!q.empty()) {
    auto x = *q.begin();
    q.erase(q.begin());
    ans.push_back(x.first.first);
    ans.push_back(x.first.second);
    for (auto& to : rg[x.second]) {
      deg[to]--;
      if (deg[to] == 0) {
        q.emplace(val[to], to);
      }
    }
  }
  assert(ans.size() == n);
  ans.resize(k);
  for (auto& i : ans) cout << i << ' ';
}