#include <bits/stdc++.h>
using namespace std;
void Onigiri() {
  int n, m;
  scanf("%d%d", &n, &m);
  int arr[n];
  priority_queue<pair<int, int>, std::vector<pair<int, int>>,
                 greater<pair<int, int>>>
      l, r;
  set<int> humans, trees;
  for (int i = 0; i < n; i++) {
    scanf("%d", &arr[i]);
    trees.insert(arr[i]);
  }
  sort(arr, arr + n);
  for (int i = 0; i < n; i++) {
    l.push({1, arr[i]});
    r.push({1, arr[i]});
  }
  long long cnt = 0, t = 1000;
  ;
  int inf = 200005;
  while (m != 0) {
    int ll = inf, rr = inf, pr, pl;
    pair<int, int> ltop = l.top();
    pair<int, int> rtop = r.top();
    ll = (ltop).first;
    pl = ltop.second;
    rr = (rtop).first;
    pr = rtop.second;
    if (trees.find(pr + rr) != trees.end() ||
        humans.find(pr + rr) != humans.end()) {
      r.pop();
      rr = inf;
    }
    if (trees.find(pl - ll) != trees.end() ||
        humans.find(pl - ll) != humans.end()) {
      l.pop();
      ll = inf;
    }
    if (l.size() == 0) break;
    if (r.size() == 0) break;
    if (rr == inf || ll == inf) continue;
    if (rr <= ll) {
      cnt += rr;
      m--;
      humans.insert(pr + rr);
      pair<int, int> p = rtop;
      p.first += 1;
      r.pop();
      if (trees.find(pr + rr + 1) == trees.end() ||
          humans.find(pr + rr + 1) == humans.end())
        r.push(p);
    } else {
      cnt += ll;
      m--;
      humans.insert(pl - ll);
      pair<int, int> p = ltop;
      p.first += 1;
      l.pop();
      if (trees.find(pl - ll - 1) == trees.end() ||
          humans.find(pl - ll - 1) == humans.end())
        l.push(p);
    }
  }
  printf("%lld\n", cnt);
  for (auto x : humans) {
    printf("%d ", x);
  }
}
signed main() {
  int t = 1;
  while (t--) {
    Onigiri();
  }
  return 0;
}
