func_code_string: #include <bits/stdc++.h>   using namespace std;   template <class T>   T sqr(T a) {     return a * a;   }   int n;   int a[21000];   int main() {     cin >> n;     for (int i = 0; i < n; i++) cin >> a[i];     int best = -1000000000;     for (int i = 3; i <= n; i++)       if (n % i == 0) {         int g = n / i;         for (int j = 0; j < g; j++) {           int cur = 0;           for (int k = j; k < n; k += g) cur += a[k];           best = max(cur, best);         }       }     cout << best;     return 0;   }   