#include <bits/stdc++.h>
using namespace std;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
long long exp(long long x, long long y) {
  x %= 1000000007;
  long long res = 1;
  while (y) {
    if (y & 1) res = res * x % 1000000007;
    x = x * x % 1000000007;
    y >>= 1;
  }
  return res;
}
long long fact(long long n) {
  long long res = 1;
  for (long long i = 2; i <= n; ++i) (res *= i) %= 1000000007;
  return res;
}
bool isprime(long long n) {
  if (n <= 1) return 0;
  for (long long i = 2; i * i <= n; ++i)
    if (n % i == 0) return 0;
  return 1;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n, m;
  cin >> n >> m;
  vector<long long> v(n);
  for (int i = 0; i < n; ++i) cin >> v[i];
  sort(v.begin(), v.end());
  long long l = 0, r = m;
  while (r > l + 1) {
    long long mid = (l + r) / 2, cnt = 2 * mid;
    for (int i = 1; i < n; ++i) {
      cnt += min(2 * mid, v[i] - v[i - 1] - 1);
    }
    if (cnt >= m)
      r = mid;
    else
      l = mid;
  }
  vector<int> ans;
  long long p = 0;
  for (int i = 0; i < n; ++i) {
    if (i && v[i] - v[i - 1] - 1 <= 2 * (r - 1)) {
      for (int j = v[i - 1] + 1; j <= v[i] - 1; ++j) {
        ans.push_back(j);
        p += min(j - v[i - 1], v[i] - j);
      }
    } else {
      if (i)
        for (int j = v[i - 1] + 1; j <= v[i - 1] + r - 1; ++j) {
          ans.push_back(j);
          p += j - v[i - 1];
        }
      for (int j = v[i] - r + 1; j <= v[i] - 1; ++j) {
        ans.push_back(j);
        p += v[i] - j;
      }
    }
  }
  for (int j = v[n - 1] + 1; j <= v[n - 1] + r - 1; ++j) {
    ans.push_back(j);
    p += j - v[n - 1];
  }
  m -= int(ans.size());
  p += m * r;
  for (int i = 0; i < n; ++i) {
    if (i == 0) {
      if (m > 0) {
        ans.push_back(v[i] - r);
        m -= 1;
      }
    } else {
      int rem = max(0ll, v[i] - v[i - 1] - 1 - 2 * (r - 1));
      if (rem > 0) {
        ans.push_back(v[i - 1] + r);
        m -= 1;
        rem -= 1;
        if (rem && m) {
          ans.push_back(v[i] - r);
          m -= 1;
        }
      }
    }
    if (m <= 0) break;
  }
  if (m > 0) ans.push_back(v[n - 1] + r);
  cout << p << '\n';
  for (auto c : ans) cout << c << " ";
  return 0;
}
