//Never stop trying
#include "bits/stdc++.h"
using namespace std;
#define boost ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)

typedef long long ll;
#define int ll
typedef string str;
typedef long double ld;
typedef pair<int, int> pi;
#define fi first
#define se second
typedef vector<int> vi;
typedef vector<pi> vpi;
#define pb push_back
#define eb emplace_back
#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define endl "\n"
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)

const int MOD = 1e9 + 7; //998244353
const ll INF = 1e18;
const int MX = 2e5 + 10;
const int nx[4] = {0, 0, 1, -1}, ny[4] = {1, -1, 0, 0}; //right left down up

template<class T> using V = vector<T>;
template<class T> bool ckmin(T& a, const T& b) { return a > b ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }
ll cdiv(ll a, ll b) { return a / b + ((a ^ b) > 0 && a % b); } // divide a by b rounded up
//constexpr int log2(int x) { return 31 - __builtin_clz(x); } // floor(log2(x))

mt19937 rng(chrono::system_clock::now().time_since_epoch().count());
//mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());
ll random(ll a, ll b){
    return a + rng() % (b - a + 1);
}
#ifndef LOCAL  
#define cerr if(false) cerr
#endif
#define dbg(x) cerr << #x << " : " << x << endl; 
#define dbgs(x,y) cerr << #x << " : " << x << " / " << #y << " : " << y << endl;
#define dbgv(v) cerr << #v << " : " << "[ "; for(auto it : v) cerr << it << ' '; cerr << ']' << endl;
#define here() cerr << "here" << endl;

void IO() {
#ifdef LOCAL
    freopen("input.txt", "r", stdin); 
    freopen("output.txt", "w", stdout);
#endif
}
/////////////////////////ONLY CLEAN CODES ALLOWED/////////////////////////


int32_t main() {
    boost; IO();

    int N; cin>>N;
    vi a(N);
    FOR(i,0,N) cin>>a[i];

    int ans=INF;
    FOR(m,0,(1<<N)){
    	if( !((m>>(N-1))&1) ) continue;
    	int cur=0; 
    	vi vec;
    	FOR(i,0,N){
    		cur|=a[i];
    		if((m>>i)&1){
    			vec.pb(cur);
    			cur=0;
    		}
		}

		int v=0;
		for(auto x: vec) v^=x; 
		ckmin(ans,v);
    }
    cout << ans << endl;
    

    return 0;
}
//Change your approach 
#include<bits/stdc++.h>
using namespace std;
#define dd double
#define ll long long int 
#define light ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define pb push_back
#define mkp make_pair
#define pi pair<ll,ll>
#define pii pair<ll,pi>
#define fi first
#define sc second
ll INF=2*1e9+5;
ll mod=998244353;
ll ans=INF,n;

void calc(vector<ll>&a , ll i,ll ro){
    if(i==n-1){
        ans = min(ans,ro);
        return;
    }
    ll rox=a[i+1];
    for (ll j = i+1; j <n ; ++j){
        calc(a,j,ro^rox);
        if(j<n-1)
            rox |= a[j+1];
    }
}

void solve(){
    cin>>n;
    vector<ll>a(n);
    for(auto &ele:a){
        cin>>ele;
    }
    ans=INF;
    ll i,rox=a[0];
    for(i=0;i<n;i++){
        calc(a,i,rox);
        if(i<n-1)
            rox |= a[i+1];  
    }
    cout<<ans<<"\n";
}

int main()
{
    #ifndef ONLINE_JUDGE
    freopen("input.txt","r",stdin);
    freopen("output.txt","w",stdout);
    #endif

    light;
    ll t;
    //cin>>t;
    t=1;
    while(t--){
        solve();
    }
}