import java.util.Arrays;

public class Main {
  private static void solve() {
    int n = ni();
    int[] s = na(n);
    int[] primes = sieveAtkin(200000);

    int md = 100;
    long[][] dp = new long[md][n];
    for (int j = 1; j < md; j++) {
      for (int i = j; i < n; i++) {
        dp[j][i] += dp[j][i - j] + s[i];
      }
    }

    n --;
    long max = 0;
    for (int a = 2; a < n; a++) {
      int last = n - a;
      int[] darr = divisors(last, primes);

      for (int d : darr) {
        if (d > a - 1 || n % d == 0 && a <= n / 2)
          continue;
        int k = (n - a) / d;
        long now = 0;
        if (d < md) {
          now = dp[d][k * d] + (dp[d][n] - dp[d][a - d]);
        } else {
          for (int i = 0; i < k; i++) {
            now += s[i * d];
            now += s[i * d + a];
          }
        }
        if (max < now) {
          max = now;
        }
      }
    }
    System.out.println(max);
  }

  public static int[] divisors(int n, int[] primes) {
    int[] div = new int[1600];
    div[0] = 1;
    int r = 1;

    for (int p : primes) {
      if (p * p > n)
        break;
      int i;
      for (i = 0; n % p == 0; n /= p, i++);
      if (i > 0) {
        for (int j = r - 1; j >= 0; j--) {
          int base = div[j];
          for (int k = 0; k < i; k++) {
            base *= p;
            div[r++] = base;
          }
        }
      }
    }
    if (n != 1) {
      for (int j = r - 1; j >= 0; j--) {
        div[r++] = div[j] * n;
      }
    }
    return Arrays.copyOf(div, r);
  }

  public static int[] sieveAtkin(int size) {
    boolean[] isPrime = new boolean[size + 1];
    int sqrtN = (int) Math.sqrt(size);
    int n;
    for (int x = 1; x <= sqrtN; ++x) {
      for (int y = 1; y <= sqrtN; ++y) {
        n = 4 * x * x + y * y;
        if (n <= size && (n % 12 == 1 || n % 12 == 5)) {
          isPrime[n] = !isPrime[n];
        }
        n = 3 * x * x + y * y;
        if (n <= size && n % 12 == 7) {
          isPrime[n] = !isPrime[n];
        }
        n = 3 * x * x - y * y;
        if (x > y && n <= size && n % 12 == 11) {
          isPrime[n] = !isPrime[n];
        }
      }
    }

    for (n = 5; n <= sqrtN; ++n) {
      if (isPrime[n]) {
        for (int k = n * n; k <= size; k += n * n) {
          isPrime[k] = false;
        }
      }
    }
    isPrime[2] = isPrime[3] = true;

    int[] ret = new int[size];
    int count = 0;
    for (int i = 1; i < size; i++) {
      if (isPrime[i]) {
        ret[count++] = i;
      }
    }
    return Arrays.copyOf(ret, count);
  }

  public static void main(String[] args) {
    new Thread(null, new Runnable() {
      @Override
      public void run() {
        long start = System.currentTimeMillis();
        String debug = args.length > 0 ? args[0] : null;
        if (debug != null) {
          try {
            is = java.nio.file.Files.newInputStream(java.nio.file.Paths.get(debug));
          } catch (Exception e) {
            throw new RuntimeException(e);
          }
        }
        reader = new java.io.BufferedReader(new java.io.InputStreamReader(is), 32768);
        solve();
        out.flush();
        tr((System.currentTimeMillis() - start) + "ms");
      }
    }, "", 64000000).start();
  }

  private static java.io.InputStream is = System.in;
  private static java.io.PrintWriter out = new java.io.PrintWriter(System.out);
  private static java.util.StringTokenizer tokenizer = null;
  private static java.io.BufferedReader reader;

  public static String next() {
    while (tokenizer == null || !tokenizer.hasMoreTokens()) {
      try {
        tokenizer = new java.util.StringTokenizer(reader.readLine());
      } catch (Exception e) {
        throw new RuntimeException(e);
      }
    }
    return tokenizer.nextToken();
  }

  private static double nd() {
    return Double.parseDouble(next());
  }

  private static long nl() {
    return Long.parseLong(next());
  }

  private static int[] na(int n) {
    int[] a = new int[n];
    for (int i = 0; i < n; i++)
      a[i] = ni();
    return a;
  }

  private static char[] ns() {
    return next().toCharArray();
  }

  private static long[] nal(int n) {
    long[] a = new long[n];
    for (int i = 0; i < n; i++)
      a[i] = nl();
    return a;
  }

  private static int[][] ntable(int n, int m) {
    int[][] table = new int[n][m];
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < m; j++) {
        table[i][j] = ni();
      }
    }
    return table;
  }

  private static int[][] nlist(int n, int m) {
    int[][] table = new int[m][n];
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < m; j++) {
        table[j][i] = ni();
      }
    }
    return table;
  }

  private static int ni() {
    return Integer.parseInt(next());
  }

  private static void tr(Object... o) {
    if (is != System.in)
      System.out.println(java.util.Arrays.deepToString(o));
  }
}


Measured memory_bytes: 315416