#include <bits/stdc++.h>
using namespace std;
using ll = int64_t;
using ld = long double;
using P = pair<int, int>;
using vs = vector<string>;
using vi = vector<int>;
using vvi = vector<vi>;
template <class T>
using PQ = priority_queue<T>;
template <class T>
using PQG = priority_queue<T, vector<T>, greater<T> >;
const int INF = 100010001;
const ll LINF = (ll)INF * INF * 10;
template <typename T1, typename T2>
inline bool chmax(T1 &a, T2 b) {
  return a < b && (a = b, true);
}
template <typename T1, typename T2>
inline bool chmin(T1 &a, T2 b) {
  return a > b && (a = b, true);
}
template <typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) {
  return is >> p.first >> p.second;
}
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
  return os << p.first << ' ' << p.second;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, p;
  cin >> n >> p;
  vi a(n);
  for (int i = 0; i < n; ++i) cin >> a[i];
  sort(a.begin(), a.end());
  int ue = a[n - 1], sita = 0;
  bool dame[4001] = {};
  int cnt[2001] = {};
  int j = 0;
  for (int i = 1; i <= a[n - 1]; i++) {
    cnt[i] = cnt[i - 1];
    while (j < n and a[j] == i) {
      j++;
      cnt[i]++;
    }
    chmax(sita, i - cnt[i]);
    for (int k = 0; k < min(i, cnt[i]); ++k) {
      if ((cnt[i] - k) % p == 0) {
        dame[i - k] = true;
      }
    }
  }
  for (int i = a[n - 1] + 1; i <= a[n - 1] + p; i++) {
    for (int k = n % p; k < min(n, i); k += p) {
      dame[i - k] = true;
    }
  }
  vi ans;
  for (int i = sita + 1; i < ue; i++)
    if (not dame[i]) {
      ans.push_back(i);
    }
  cout << ans.size() << endl;
  for (int i = 0; i < ans.size(); ++i) {
    cout << ans[i] << (i == ans.size() - 1 ? '\n' : ' ');
  }
}
