#include <bits/stdc++.h>
using namespace std;
int n;
string s;
int tot = 2;
int t[4000000][2];
int a[100020];
void add(int c) {
    int h = 1;
    for (int i = 30; i > -1; i--) {
        int ci = (c >> i) & 1;
        if (t[h][ci] <= 0) {
            t[h][ci] = tot;
            tot++;
        }
        h = t[h][ci];
    }
    return;
}
int query(int c) {
    int h = 1;
    int sum = 0;
    for (int i = 30; i > -1; i--) {
        int ci = (c >> i) & 1;
        if (t[h][1 - ci] > 1) {
            sum += (1 << i);
            h = t[h][1 - ci];
        } else {
            h = t[h][ci];
        }
    }
    return sum;
}
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> a[i];
        add(a[i]);
    }
    int maxl = 0;
    for (int i = 0; i < n; i++) {
        maxl = max(maxl, query(a[i]));
    }
    cout << maxl;
    return 0;
}