func_code_string: #include <bits/stdc++.h>   using namespace std;   long long nCr(int n, int r) {     if (r > n - r) r = n - r;     long long ans = 1;     int i;     for (i = 1; i <= r; i++) {       ans *= n - r + i;       ans /= i;     }     return ans;   }   int main() {     ios::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     ;     long long a, b, c, d, e, g, h, n, t, f, k, l, m,         f1 = 0, flag = 0, flag1 = 0, co = 0, co1 = 0, co2 = 0, arr1[100001] = {0},         arr[100001] = {0}, sum = 0, sum1 = 0, ma = 0, mi = 1000000000000000001;     long long co3 = 0, co4 = 0, co5 = 0, co6 = 0, co7 = 0, co8 = 0;     double pi = 2 * acos(0.0);     string str, str1, str2, str3;     char ch;     vector<long long> v;     vector<long long> v1;     vector<string> vs;     vector<string> vs1;     map<int, int> mp;     set<long long> s;     set<long long> s1;     set<long long>::iterator it;     queue<long long> q;     int x[] = {1, 1, 1, 0, 0, -1, -1, -1};     int y[] = {0, 1, -1, 1, -1, 1, -1, 0};     cin >> a >> b;     for (int i = 0; i < a; i++) {       cin >> c;       mp[c] = 1;     }     for (int i = 1;; i++) {       if (mp[i] == 1)         continue;       else {         b -= i;         if (b < 0) break;         v.push_back(i);       }     }     cout << v.size() << endl;     for (int i = 0; i < v.size(); i++) cout << v[i] <<    ;     return 0;   }   