#include <bits/stdc++.h>
using namespace std;
map<long long, long long> dist;
int main() {
  long long n, m;
  cin >> n >> m;
  long long x;
  queue<long long> q;
  for (long long i = 0; i < n; i++) {
    cin >> x;
    dist[x] = 0;
    q.push(x);
  }
  long long total = 0;
  vector<long long> ans;
  while (!q.empty()) {
    x = q.front();
    q.pop();
    if (dist[x] != 0) {
      ans.push_back(x);
      total += (dist[x]);
      if (ans.size() == m) break;
    }
    if (dist.find(x - 1) == dist.end()) {
      q.push(x - 1);
      dist[x - 1] = dist[x] + 1;
    }
    if (dist.find(x + 1) == dist.end()) {
      q.push(x + 1);
      dist[x + 1] = dist[x] + 1;
    }
  }
  cout << total << "\n";
  for (long long i = 0; i < ans.size(); i++) {
    cout << ans[i] << " ";
  }
  return 0;
}
