func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n, x, a[5] = {0};     cin >> n;     for (int i = 0; i < n; i++) {       cin >> x;       a[x]++;     }     int res = a[4];     res += a[2] / 2;     a[2] = a[2] % 2;     if (a[2] == 1) {       res++;       a[1] -= 2;     }     res += a[3];     if (a[1] > a[3]) {       a[1] -= a[3];       res += (a[1] + 3) / 4;     }     cout << res;     return 0;   }   