func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n;     cin >> n;     int a[n];     map<int, int> m;     int u = 0;     long long powers[32];     powers[0] = 1;     for (int i = 1; i < 32; i++) powers[i] = 2 * powers[i - 1];     for (int i = 0; i < n; i++) {       cin >> a[i];       m[a[i]]++;     }     bool flag = false;     for (int i = 0; i < n; i++) {       flag = false;       for (int j = 0; j < 32; j++) {         long long x = powers[j] - a[i];         if (m[x] > 1 || (m[x] == 1 && x != a[i])) {           flag = true;           break;         }       }       if (!flag) u++;     }     cout << u << endl;     return 0;   }   