#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
constexpr int INF = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-8;
constexpr int MOD = 998244353;
// constexpr int MOD = 1000000007;
constexpr int DY4[]{1, 0, -1, 0}, DX4[]{0, -1, 0, 1};
constexpr int DY8[]{1, 1, 0, -1, -1, -1, 0, 1};
constexpr int DX8[]{0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U>
inline bool chmax(T& a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U>
inline bool chmin(T& a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    std::cout << fixed << setprecision(20);
  }
} iosetup;

int main() {
  constexpr int B = 16;
  int n; cin >> n;
  if (n >= B) {
    cout << (1 << B) - 1 << '\n';
    return 0;
  }
  bool dp[1 << B]{};
  dp[0] = true;
  while (n--) {
    int a; cin >> a;
    bool nxt[1 << B]{};
    REP(_, B) {
      REP(i, 1 << B) {
        if (dp[i]) nxt[i | a] = true;
      }
      a = (a / 2) | ((a & 1) << (B - 1));
    }
    swap(dp, nxt);
  }
  for (int i = (1 << B) - 1; i >= 0; --i) {
    if (dp[i]) {
      cout << i << '\n';
      break;
    }
  }
  return 0;
}