#include <bits/stdc++.h>
using namespace std;
long long mul(long long a, long long b, long long p = 1000000007) {
  return ((a % p) * (b % p)) % p;
}
long long add(long long a, long long b, long long p = 1000000007) {
  return (a % p + b % p) % p;
}
void input(long long a[], long long sz) {
  for (long long i = 0; i < sz; i++) cin >> a[i];
}
void print(long long a[], long long sz) {
  for (long long i = 0; i < sz; i++) {
    if (i == sz - 1)
      cout << a[i] << "\n";
    else
      cout << a[i] << " ";
  }
}
long long maxr(long long a[], long long sz) {
  long long ma;
  for (long long i = 0; i < sz; i++) {
    if (i == 0)
      ma = a[i];
    else if (a[i] > ma)
      ma = a[i];
  }
  return ma;
}
long long minr(long long a[], long long sz) {
  long long mi;
  for (long long i = 0; i < sz; i++) {
    if (i == 0)
      mi = a[i];
    else if (a[i] < mi)
      mi = a[i];
  }
  return mi;
}
long long isprm(long long n) {
  if (n <= 1) return 0;
  if (n <= 3) return 1;
  if (n % 2 == 0 || n % 3 == 0) return 0;
  for (int i = 5; i * i <= n; i = i + 6)
    if (n % i == 0 || n % (i + 2) == 0) return 0;
  return 1;
}
long long power(long long x, long long y, long long p = 1000000007) {
  long long res = 1;
  x = x % p;
  while (y > 0) {
    if (y & 1) res = (res * x) % p;
    y = y >> 1;
    x = (x * x) % p;
  }
  return res;
}
long long modInverse(long long n, long long p = 1000000007) {
  return power(n, p - 2, p);
}
long long ncrMod(long long n, long long r, long long p = 1000000007) {
  if (r == 0) return 1;
  long long fac[n + 1];
  fac[0] = 1;
  for (long long i = 1; i <= n; i++) fac[i] = fac[i - 1] * i % p;
  return (fac[n] * modInverse(fac[r], p) % p * modInverse(fac[n - r], p) % p) %
         p;
}
struct comp {
  bool operator()(const pair<long long, long long> &a,
                  const pair<long long, long long> &b) const {
    if (a.first == b.first) {
      return (a.second > b.second);
    }
    return (a.first < b.first);
  }
};
long long solve(vector<bitset<30>> b, long long i) {
  if (i < 0) return 0;
  vector<bitset<30>> x, y;
  long long n = b.size(), ans = 0;
  for (long long j = 0; j < n; j++) {
    if (b[j][i] == 0)
      x.push_back(b[j]);
    else
      y.push_back(b[j]);
  }
  if (x.size() == 0)
    ans += solve(y, i - 1);
  else if (y.size() == 0)
    ans += solve(x, i - 1);
  else
    ans += (pow(2, i) + min(solve(y, i - 1), solve(x, i - 1)));
  return ans;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  long long n;
  cin >> n;
  long long a[n + 5];
  input(a, n);
  vector<bitset<30>> b(n);
  for (long long i = 0; i < n; i++) b[i] = a[i];
  long long ans = solve(b, 30);
  cout << ans << "\n";
  return 0;
}
