#include <bits/stdc++.h>
using namespace std;
int inf = 1e9;
const int N = 2e5 + 10;
int n, m, cnt;
int a[N], ans[N];
map<int, int> mp;
set<int> st;
vector<int> v;
long long sum = 0;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> m;
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
    st.insert(a[i]);
    mp[a[i]] = 1;
  }
  sort(a + 1, a + 1 + n);
  int j = 1;
  for (j = 1;; j++) {
    bool f = 0;
    int y = 0;
    for (auto x : st) {
      if (mp[x - j] && mp[x + j]) {
        v.push_back(x);
        continue;
      }
      f = 0;
      if (!mp[x - j]) {
        cnt++;
        mp[x - j] = 1;
        ans[cnt] = x - j;
        sum += j;
      }
      if (!mp[x + j]) {
        cnt++;
        mp[x + j] = 1;
        ans[cnt] = x + j;
        sum += j;
      }
      y = x;
      if (cnt > m) {
        sum -= j;
        break;
      }
      if (cnt == m) break;
    }
    for (auto x : v) st.erase(x);
    v.clear();
    if (cnt >= m || st.size() == 0) break;
  }
  cout << sum << "\n";
  for (int i = 1; i <= m; i++) cout << ans[i] << " ";
}
