#include <bits/stdc++.h>
using namespace std;
struct custom_hash {
  static uint64_t splitmix64(uint64_t x) {
    x += 0x9e3779b97f4a7c15;
    x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
    x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
    return x ^ (x >> 31);
  }
  size_t operator()(uint64_t x) const {
    static const uint64_t FIXED_RANDOM =
        chrono::steady_clock::now().time_since_epoch().count();
    return splitmix64(x + FIXED_RANDOM);
  }
};
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n, k;
  cin >> n >> k;
  int a[n], x;
  deque<int> dq;
  unordered_set<int, custom_hash> s;
  for (int i = 0; i < n; i++) {
    cin >> x;
    if (dq.empty()) {
      dq.push_back(x);
      s.insert(x);
      continue;
    }
    if (s.find(x) != s.end()) {
      continue;
    } else {
      if (dq.size() >= k) {
        s.erase(dq.back());
        dq.pop_back();
        dq.push_front(x);
        s.insert(x);
      } else {
        dq.push_front(x);
        s.insert(x);
      }
    }
  }
  cout << dq.size() << "\n";
  for (int i : dq) {
    cout << i << " ";
  }
  cout << "\n";
  return 0;
}
