#include <sstream>
#include <string>
#include <vector>
#include <map>
#include <algorithm>
#include <iostream>
#include <utility>
#include <set>
#include <cctype>
#include <queue>
#include <stack>
#include <cstdio>
#include <cstdlib>
#include <cmath>

#define INF 1000000000

using namespace std;
typedef long long ll;

const int MAXN = 100010;

int dfs(int bit, vector<int>& v) {
    if (bit == 0) {
        int ret = 0;
        for (int i = 0; i < (int)v.size(); i++) {
            ret ^= v[i];
        }
        return ret;
    }
    if (v.size() <= 1) return 0;
    vector<int> bit0, bit1;
    for (int i = 0; i < (int)v.size(); i++) {
        if (v[i] >> bit & 1) bit1.push_back(v[i]);
        else bit0.push_back(v[i]);
    }
    if (bit0.empty()) return dfs(bit-1, bit1);
    if (bit1.empty()) return dfs(bit-1, bit0);
    return (1<<bit) + min(dfs(bit-1, bit0), dfs(bit-1, bit1));
}

int main(void) {
    int N;
    cin >> N;
    vector<int> a(N);
    for (int i = 0; i < N; i++) cin >> a[i];
    cout << dfs(30, a) << endl;
    return 0;
}