#include <bits/stdc++.h>
#include "atcoder/all"
#define debug cout << "OK" << endl;
template<typename T>
inline bool chmax(T& a, const T b) { if (a < b) { a = b; return true; } return false; }
template<typename T>
inline bool chmin(T& a, const T b) { if (a > b) { a = b; return true; } return false; }
inline int Code(char c) {
	if ('A' <= c and c <= 'Z')return (int)(c - 'A');
	if ('a' <= c and c <= 'z')return (int)(c - 'a');
	if ('0' <= c and c <= '9')return (int)(c - '0');
	assert(false);
}
using namespace std;
using namespace atcoder;
using minit = modint1000000007;
constexpr int MOD = 1000000007;
constexpr int MOD2 = 998244353;
constexpr long long INF = (1LL << 63);

template<typename T>
ostream& operator << (ostream& st, const vector<T>& v) {
	for (const T value : v) {
		st << value << " ";
	}
	return st;
}
template<typename T>
istream& operator >> (istream& st, vector<T>& v) {
	for (T& value : v) {
		st >> value;
	}
	return st;
}

long long pow_(const int a, const int b, const int m = INF) {
	long long res = 1;
	long long base = a;
	for (int i = 0; i < 64; i++) {
		if (b & (1ll << i))res *= base;
		res %= m;
		base = base * base;
		base %= m;
	}
	return res;
}
inline int gcd(const int a, const int b) { return (b == 0 ? a : gcd(b, a % b)); }
inline int lcm(const int a, const int b) { return a * b / gcd(a, b); }
//
class nCk {
public:
	const int m;
	const int MAXIMUM = 1000000;
	vector<int> fac, facinv, inv;
	nCk(int m_);
	~nCk();
	int com(int n, int k)const;
};
nCk::nCk(int m_):m(m_) {
	fac.resize(MAXIMUM + 3);
	facinv.resize(MAXIMUM + 3);
	inv.resize(MAXIMUM + 3);
	fac[0] = fac[1] = 1;
	facinv[0] = facinv[1] = 1;
	inv[1] = 1;
	for (int i = 2; i < MAXIMUM + 2; i++) {
		fac[i] = fac[i - 1] * i % m;
		inv[i] = m - inv[m % i] * (m / i) % m;
		facinv[i] = facinv[i - 1] * inv[i] % m;
	}
}
nCk::~nCk(){}
int nCk::com(int n, int k)const {
	if (n < k)return 0;
	assert(!(n < 0 || k < 0));
	return fac[n] * (facinv[k] * facinv[n - k] % m) % m;
}
template<typename T>
vector<long long> press(const vector<T>& arr) {
	vector<T> X = arr;
	sort(X.begin(), X.end());
	X.erase(unique(X.begin(), X.end()), X.end());
	vector<long long> ans(arr.size());
	for (int i = 0; i < arr.size(); i++) {
		ans[i] = lower_bound(X.begin(), X.end(), arr[i]) - X.begin();
	}
	return ans;
}

//

class Solver {
public:
	int T;
	Solver() :T(1) {}
	~Solver(){}
	void ios()const;
	void multi();
	void solve() const;
	void sp(int x)const;
	void ft()const;

	//
	
	//
};
void Solver::ios() const {
	cin.tie(nullptr);
	ios_base::sync_with_stdio(false);
	return;
}
void Solver::multi() {
	cin >> T;
	return;
}
void Solver::sp(const int x)const {
	cout << fixed << setprecision(x) << endl;
	return;
}

void Solver::ft() const {
	
}
void Solver::solve() const {
	int N;
	cin >> N;
	vector<int> A(N);
	cin >> A;
	int ans = 0;
	for (int i = 0; i < 34; i++) {
		vector<bool> f;
		for (const int a : A) {
			f.push_back((bool)(a & (1ll << i)));
		}
		bool base = f[0];
		for (const bool flag : f) {
			if (flag != base) {
				ans |= (1ll << i);
			}
		}
	}
	cout << ans << endl;
}

signed main() {
	Solver solver;
	solver.ios();
	//solver.ft();
	//solver.multi();
	//solver.sp();
	for (int i = 0; i < solver.T; i++)
		solver.solve();
	return 0;
}

/*
* わらびのコードこーどすぺーす
 (σ･∀･)σｹﾞｯﾂ!!
*/