#include <stack>
#include <queue>
#include <set>
#include <vector>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <string>
#include <utility>
#include <climits>
#include <algorithm>
#include <numeric>
#include <cmath>
#include <cstring>
#include <iostream>
#include <fstream>
#include <iomanip>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<ll,int> pli;
typedef pair<int,ll> pil;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<ll> vl;
 
#define mp make_pair
#define fr first
#define sc second

#define show(x) cerr << "LINE" << __LINE__ << " : " << #x << " = " << (x) << endl
#define rep(s, i, n) for (int(i) = (s); (i) < (n); (i)++)
#define repe(s, i, n) for (int(i) = (s); (i) <= (n); (i)++)
#define rrep(s, i, n) for (int(i) = (s); (i) > (n); (i)--)
#define rrepe(s, i, n) for (int(i) = (s); (i) >= (n); (i)--)
#define allof(a) (a).begin(), (a).end()

int res=INT_MAX;
int n;

void cal(vi &a,int index,int xo){
    if(n==index){
        res=min(res,xo);
    }

    int nowor=0;
    rep(index,i,n){
        nowor|=a[i];
        cal(a,i+1,xo^nowor);
    }
}

int main(int argc, char const *argv[])
{
    cin>>n;
    vi a(n);
    rep(0,i,n)cin>>a[i];
    cal(a,0,0);

    cout<<res<<endl;
    
    return 0;
}

#include <bits/stdc++.h>
#if __has_include(<atcoder/all>)
#include <atcoder/all>
using namespace atcoder;
#endif
using namespace std;
using ll = long long;
struct Edge
{
    ll to;
    ll cost;
};
using Graph = vector<vector<Edge>>;
using P = pair<ll, ll>;
#define mp make_pair
#define REP(i, n) for (int i = 0; i < (n); ++i)
#define SORT(v) sort((v).begin(), (v).end())
#define RSORT(v) sort((v).rbegin(), (v).rend())
#define ALL(v) (v).begin(), v.end()
const ll MOD = 1000000007;
const ll nmax = 8;
const ll INF = LLONG_MAX;
const int MAX = 510000;
bool graph[nmax][nmax];
long long fac[MAX], finv[MAX], inv[MAX];

void COMinit()
{
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (int i = 2; i < MAX; i++)
    {
        fac[i] = fac[i - 1] * i % MOD;
        inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD;
        finv[i] = finv[i - 1] * inv[i] % MOD;
    }
}

ll COM(int n, int k)
{
    if (n < k)
        return 0;
    if (n < 0 || k < 0)
        return 0;

    return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}

vector<vector<ll>> dist = vector<vector<ll>>(nmax, vector<ll>(nmax, INF));
void warshall_floyd(ll n)
{
    for (size_t i = 0; i < n; i++)
    {
        for (size_t j = 0; j < n; j++)
        {
            for (size_t k = 0; k < n; k++)
            {
                dist[j][k] = min(dist[j][k], dist[j][i] + dist[i][k]);
            }
        }
    }
}

ll gcd(ll a, ll b)
{
    if (b == 0)
        return a;
    return gcd(b, a % b);
}

ll lcm(ll a, ll b)
{
    ll g = gcd(a, b);
    return a / g * b;
}

ll mulMod(ll a, ll b)
{
    return (((a % MOD) * (b % MOD)) % MOD);
}

ll powMod(ll a, ll p)
{
    if (p == 0)
    {
        return 1;
    }
    else if (p % 2 == 0)
    {
        ll half = powMod(a, p / 2);
        return mulMod(half, half);
    }
    else
    {
        return mulMod(powMod(a, p - 1), a);
    }
}

ll ceil(ll a, ll b)
{
    return (a + b - 1) / b;
}

void solve(long long N, std::vector<long long> A)
{
    ll ans = INF;
    for (int bit = 0; bit < (1 << (N - 1)); bit++)
    {
        vector<ll> stock;
        ll now = A[0];
        for (int i = 0; i < N - 1; i++)
        {
            if (bit & (1 << i))
            {
                now = now | A[i + 1];
            }
            else
            {
                stock.push_back(now);
                now = A[i + 1];
            }
        }
        stock.push_back(now);

        ll score = stock[0];
        for (int i = 1; i < stock.size(); i++)
        {
            score ^= stock[i];
        }

        ans = min(ans, score);
    }

    cout << ans << endl;
}

int main()
{

    long long N;
    scanf("%lld", &N);
    std::vector<long long> A(N);
    for (int i = 0; i < N; i++)
    {
        scanf("%lld", &A[i]);
    }
    solve(N, std::move(A));
    return 0;
}
