#include <bits/stdc++.h>
#define rep(i, n) for (long long i = 0; i < (int)(n); i++)
#define put(i) cout << fixed << i << endl
using namespace std;
using ll = long long;

void bubbleSort(vector<ll> a, ll array_size) {
    ll i, j, k;

    for (i = 0; i < (array_size - 1); i++) {
        for (j = (array_size - 1); j > i; j--) {
            if (a[j] < a[j - 1]) {
                k = a[j];
                a[j] = a[j - 1];
                a[j - 1] = k;
            }
        }
    }
}

int main() {
    ll n;
    cin >> n;
    ll ans, maxa = 0;
    vector<ll> a(n), b(n - 1);
    rep(i, n) cin >> a[i];
    vector<vector<ll>> nest(n * n);
    // kokodenantokasuru
    sort(a.begin(), a.end(), greater<ll>());

    
    ll k, cnt = 0;
    for (ll i = 0; i < (n - 1); i++) {
        for (ll j = (n - 1); j > i; j--) {
            if (a[j] < a[j - 1]) {
                k = a[j];
                a[j] = a[j - 1];
                a[j - 1] = k;
            }
            nest[cnt++] = a;
        }
    }


    for(long long j = 0; j < cnt; j++) {
        vector<ll> x = nest[j];
        for (long long i = 0; i < n - 1; i++) {
            b[i] = x[i] xor x[i + 1];
        }

        ans = b[0];
        for (long long i = 1; i < n - 1; i++) {
            ans = ans xor b[i];
        }
        maxa = max(ans, maxa);
    }

    put(maxa);
}