#include <iostream>
#include <algorithm>

using namespace std;
const int N = 100010, M = 31 * N + 10;

int n;
int a[N], son[M][2], idx;

void insert(int x) {
    int p = 0;
    for (int i = 30; i >= 0; i--) {
        int u = x >> i & 1;
        if (!son[p][u])  son[p][u] = ++idx;
            p = son[p][u];
    }
}


int query(int x) {
    int p = 0, res = 0;
    for (int i = 30; i >= 0; i--) {
        int u = x >> i & 1;

        if (son[p][!u]) {
            p = son[p][!u];
            res = res * 2 + !u;
        } else {
            p = son[p][u];
            res = res * 2 + u;
        }
    }

    return res;
}


int main () {
    cin >> n;
    for (int i = 0; i < n; i++) scanf("%d", &a[i]);

    int res = 0;
    for (int i = 0; i < n; i++) {
        insert(a[i]);
        int t = query(a[i]);
        res = max(res, a[i] ^ t);
    }

    cout << res;
    return 0;
}