func_code_string: #include <bits/stdc++.h>   using namespace std;   int mod = 1e9 + 7;   bool prime[1000001] = {true};   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     int n, m;     cin >> n >> m;     vector<int> arr(m);     if (m == 0) {       cout <<  YES ;       return 0;     }     for (int i = 0; i < m; i++) {       cin >> arr[i];     }     sort(arr.begin(), arr.end());     if (arr[0] == 1 || arr[m - 1] == n) {       cout <<  NO ;       return 0;     } else {       for (int i = 0; i < m - 1; i++) {         if (i < m - 2 && arr[i] + 1 == arr[i + 1] &&             arr[i + 1] + 1 == arr[i + 2]) {           cout <<  NO ;           return 0;         }       }       cout <<  YES ;     }     return 0;   }   