#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k;
  cin >> n >> k;
  queue<int> q;
  set<int> vals;
  for (int i = 0; i < n; ++i) {
    int id;
    cin >> id;
    if (!vals.count(id)) {
      if (int(q.size()) >= k) {
        int cur = q.front();
        q.pop();
        vals.erase(cur);
      }
      vals.insert(id);
      q.push(id);
    }
  }
  vector<int> res;
  while (!q.empty()) {
    res.push_back(q.front());
    q.pop();
  }
  reverse(res.begin(), res.end());
  cout << res.size() << endl;
  for (auto it : res) cout << it << " ";
  cout << endl;
  return 0;
}
