#include <bits/stdc++.h>
using namespace std;

using ll = long long;
#define rep(i,n) for (ll i=0; i<(ll)(n); i++)

int main() {
	int n; cin >> n;
	vector<ll> cnt(1<<15);
	vector<ll> oe(1<<15);
	rep(i, n) {
		int x; cin >> x;
		int e=0, o=0;
		rep(b, 30) if ((x>>b)&1) {
			if (b%2 == 0) e |= 1<<(b/2);
			else o |= 1<<(b/2);
		}
		cnt[e]++;
		oe[e] |= o;
	}
	vector<ll> AND(1<<15, (1<<15)-1), OR(1<<15), CNT(1<<15);
	rep(i, 1<<15) if (0 < cnt[i]) {
		AND[i] = i;
		OR[i] = oe[i];
		CNT[i] = cnt[i];
	}
	rep(b, 15) rep(i, 1<<15) if (((i>>b)&1) == 0) {
		AND[i] &= AND[i|(1<<b)];
		OR[i] |= OR[i|(1<<b)];
		CNT[i] += CNT[i|(1<<b)];
	}
	ll ans = 0;
	rep(i, 1<<15) if (CNT[i] != 0) {
		ll ans2 = 0;
		rep(b, 15) {
			if ((AND[i]>>b)&1) ans2 |= 1<<(2*b);
			if ((OR[i]>>b)&1) ans2 |= 1<<(2*b+1);
		}
		ans = max(ans, ans2);
	}
	cout << ans << endl;
}