#include <bits/stdc++.h>
using namespace std;
long long int c[300020];
vector<long long int> tree[1200080];
set<long long int> ans;
void build(long long int node, long long int st, long long int ed) {
  if (st == ed) {
    tree[node].push_back(c[st]);
    return;
  }
  long long int mid = (st + ed) / 2;
  build(2 * node, st, mid);
  build(2 * node + 1, mid + 1, ed);
  long long int siz1 = tree[2 * node].size();
  long long int siz2 = tree[2 * node + 1].size();
  tree[node].resize(siz1 + siz2);
  merge(tree[2 * node].begin(), tree[2 * node].end(),
        tree[2 * node + 1].begin(), tree[2 * node + 1].end(),
        tree[node].begin());
}
bool query(long long int node, long long int st, long long int ed,
           long long int l, long long int r, long long int x) {
  if (r < st || ed < l) {
    return 0;
  }
  if (l <= st && ed <= r) {
    auto it = lower_bound(tree[node].begin(), tree[node].end(), x);
    if (it == tree[node].end()) return 0;
    if ((*it) != x) return 0;
    return 1;
  }
  long long int mid = (st + ed) / 2;
  bool ans1 = query(2 * node, st, mid, l, r, x);
  bool ans2 = query(2 * node + 1, mid + 1, ed, l, r, x);
  return (ans1 | ans2);
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long int n, p, i;
  cin >> n >> p;
  long long int a[n];
  for (i = 0; i < n; ++i) cin >> a[i];
  sort(a, a + n);
  long long int l = a[n - 1] - n + 1, r = a[n - 1] + n - 1;
  l = max((long long int)(1), l);
  for (i = l; i <= r; ++i) {
    long long int val = upper_bound(a, a + n, i) - a;
    c[i - l + 1] = ((i - val) % p + p) % p;
  }
  build(1, 1, r - l + 1);
  for (i = l; i < a[n - 1]; ++i) {
    if (!query(1, 1, r - l + 1, i - l + 1, i - l + n, (i % p))) ans.insert(i);
  }
  cout << (long long int)(ans.size()) << "\n";
  for (auto its : ans) cout << its << " ";
  return 0;
}
