#include <bits/stdc++.h>
using namespace std;
long long int bg = 9982443530987;
long long int power(long long int x, long long int y) {
  if (x == 0) return 0;
  if (y == 0) return 1;
  long long int s = y / 2;
  long long int f = power(x, s);
  if (y % 2 == 0)
    return (f * f);
  else
    return f * f * x;
}
void boom() {
  long long int i, n, h, j, m;
  cin >> n >> m;
  long long int arr[n];
  set<pair<long long int, long long int> > set1;
  set<long long int> f;
  for (i = 0; i < n; i++) {
    cin >> arr[i];
    f.insert(arr[i]);
  }
  sort(arr, arr + n);
  for (i = 0; i < n; i++) {
    if (f.find(arr[i] - 1) == f.end()) set1.insert(make_pair(1, arr[i] - 1));
    if (f.find(arr[i] + 1) == f.end()) set1.insert(make_pair(1, arr[i] + 1));
  }
  set<long long int> vec1;
  long long int sum = 0;
  while (set1.size() != 0) {
    pair<long long int, long long int> r = *(set1.begin());
    set1.erase(make_pair(r.first, r.second));
    if (f.find(r.second) == f.end()) {
      sum += r.first;
      vec1.insert(r.second);
      long long int k = r.second;
      f.insert(r.second);
      if (f.find(k - 1) == f.end())
        set1.insert(make_pair(r.first + 1, k - 1));
      else if (f.find(k + 1) == f.end())
        set1.insert(make_pair(r.first + 1, k + 1));
      if (vec1.size() == m) break;
    }
  }
  cout << sum << '\n';
  for (set<long long int>::iterator d = vec1.begin(); d != vec1.end(); d++)
    cout << *d << " ";
}
int main() {
  long long int top;
  top = 1;
  while (top--) boom();
  return 0;
}
