func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     long long int n, m;     cin >> n >> m;     if (m == 0) {       cout <<  YES  << endl;       return 0;     }     vector<long long int> v(m);     for (long long int i = 0; i < m; cin >> v[i++])       ;     sort(v.begin(), v.end());     if (v[0] == 1 || v[m - 1] == n) {       cout <<  NO  << endl;       return 0;     }     int ind = 1, ans = 0;     for (int i = 0; i < (m - 2); i++) {       if ((v[i] == (v[i + 1] - 1)) && (v[i + 1] == (v[i + 2] - 1))) {         cout <<  NO  << endl;         return 0;       }     }     cout <<  YES  << endl;   }   