#pragma region kyomukyomupurin

/**
 *    author  : 𝒌𝒚𝒐𝒎𝒖𝒌𝒚𝒐𝒎𝒖𝒑𝒖𝒓𝒊𝒏
 *    created : 2020-07-24 17:01:24
 **/

#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <chrono>
#include <cmath>
#include <complex>
#include <cstring>
#include <deque>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <utility>
#include <vector>

using namespace std;

using int64 = long long;

template <class T>
inline void eraque(std::vector<T>& vec) {
  vec.erase(std::unique(vec.begin(), vec.end()), vec.end());
  return;
}

template <class T>
inline int lower_position(const std::vector<T>& vec, T val) {
  return static_cast<int>(std::distance(vec.begin(), std::lower_bound(vec.begin(), vec.end(), val)));
}

template <class T>
inline int upper_position(const std::vector<T>& vec, T val) {
  return static_cast<int>(std::distance(vec.begin(), std::upper_bound(vec.begin(), vec.end(), val)));
}

template<class T>
inline std::string to_binary(T n) {
  assert(n > 0);
  std::string ret = "";
  while (n) ret += (n & 1) ? '1' : '0', n >>= 1;
  std::reverse(ret.begin(), ret.end());
  return ret;
}

template <class T>
inline void println(T val) {
  std::cout << val << '\n';
}

template <class T>
using binary_heap = std::priority_queue<T, std::vector<T>, std::greater<T>>;

template <class T, class U>
std::ostream& operator<<(std::ostream& os, const std::pair<T, U>& p) {
  return os << '(' << p.first << ", " << p.second << ')';
}

template <class Tuple, std::size_t... Is>
void tuple_out(std::ostream& os, const Tuple& tp, std::index_sequence<Is...>) {
  ((os << (Is ? ", " : "(") << std::get<Is>(tp)), ...) << ")";
}

template <class... Args>
std::ostream& operator<<(std::ostream& os, const std::tuple<Args...>& tp) {
  tuple_out(os, tp, std::index_sequence_for<Args...>{});
  return os;
}

template <class T>
std::ostream& operator<<(std::ostream& os, const std::vector<T>& vec) {
  int n = 0;
  for (auto e : vec) os << (n++ ? ", " : "{") << e;
  return os << (n ? "}" : "{}");
}

template <class T, class Compare>
std::ostream& operator<<(std::ostream& os, const std::set<T, Compare>& st) {
  int n = 0;
  for (auto e : st) os << (n++ ? ", " : "{") << e;
  return os << (n ? "}" : "{}");
}

template <class T, class U, class Compare>
std::ostream& operator<<(std::ostream& os, const std::map<T, U, Compare>& mp) {
  int n = 0;
  for (auto e : mp) os << (n++ ? ", " : "{") << e;
  return os << (n ? "}" : "{}");
}

template <class T>
std::istream& operator>>(std::istream& is, std::vector<T>& vec) {
  for (T& e : vec) is >> e;
  return is;
}

template <class T, class U>
std::istream& operator>>(std::istream& is, std::pair<T, U>& p) {
  return is >> p.first >> p.second;
}

template <class Tuple, std::size_t... Is>
void tuple_in(std::istream& is, Tuple& tp, std::index_sequence<Is...>) {
  ((is >> std::get<Is>(tp)), ...);
}

template <class... Args>
std::istream& operator>>(std::istream& is, std::tuple<Args...>& tp) {
  tuple_in(is, tp, std::index_sequence_for<Args...>{});
  return is;
}

#define all(_) begin(_), end(_)
#define rall(_) rbegin(_), rend(_)

#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]: ", debug_out(__VA_ARGS__)
#else
#define debug(...)
#endif

void debug_out() { std::cerr << '\n'; }

template <class Head, class... Tail>
void debug_out(Head&& head, Tail&&... tail) {
  std::cerr << head;
  if (sizeof...(Tail) != 0) std::cerr << ", ";
  debug_out(std::forward<Tail>(tail)...);
}

#pragma endregion kyomukyomupurin

template <class T, class F>
class SaprseTable {
  // F must be idempotent function!
 public:
  SaprseTable(const std::vector<T>& data, F f)
      : n_((int)data.size()), lg_(32 - __builtin_clz(n_)), f_(f), data_(data) {
    build();
  }

  // return f_[l, r]
  T query(int l, int r) {
    assert(0 <= l && l <= r && r < n_);
    int lg = 32 - __builtin_clz(r - l + 1) - 1;
    return f_(tab_[lg][l], tab_[lg][r - (1 << lg) + 1]);
  }

 private:
  int n_;
  int lg_;
  F f_;
  std::vector<T> data_;
  std::vector<std::vector<T>> tab_;

  void build() {
    tab_.resize(lg_);
    tab_[0] = data_;
    for (int j = 1; j < lg_; ++j) {
      tab_[j].resize(n_ - (1 << j) + 1);
      for (int i = 0; i <= n_ - (1 << j); ++i) {
        tab_[j][i] = f_(tab_[j - 1][i], tab_[j - 1][i + (1 << (j - 1))]);
      }
    }
  }
};

unsigned long long fast_gcd(unsigned long long x, unsigned long long y) {
  int shift;
  if (x == 0) return y;
  if (y == 0) return x;
  shift = __builtin_ctzll(x | y);
  x >>= __builtin_ctzll(x);
  do {
    y >>= __builtin_ctzll(y);
    if (x > y) std::swap(x, y);
    y -= x;
  } while (y);
  return x << shift;
}

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);

  int n; cin >> n;
  vector<int> a(n); cin >> a;
  auto f = [](int x, int y){ return fast_gcd(x, y); };
  SaprseTable st(a, f);

  int ans = 0;

  ans = max(ans, st.query(0, n - 2));
  ans = max(ans, st.query(1, n - 1));

  for (int i = 1; i < n - 1; ++i) {
    ans = max(ans, (int)fast_gcd(st.query(0, i - 1), st.query(i + 1, n - 1)));
  }

  println(ans);

  return 0;
}


Measured memory_bytes: 10056