#ifdef LOCAL111
#else
	#define NDEBUG
#endif
#include <bits/stdc++.h>
const int INF = 1e9;
using namespace std;
template<typename T, typename U> ostream& operator<< (ostream& os, const pair<T,U>& p) { cout << '(' << p.first << ' ' << p.second << ')'; return os; }

#define endl '\n'
#define ALL(a)  (a).begin(),(a).end()
#define SZ(a) int((a).size())
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define REP(i,n)  FOR(i,0,n)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)
#define RBP(i,a) for(auto& i : a)
#ifdef LOCAL111
	#define DEBUG(x) cout<<#x<<": "<<(x)<<endl
	template<typename T> void dpite(T a, T b){ for(T ite = a; ite != b; ite++) cout << (ite == a ? "" : " ") << *ite; cout << endl;}
#else
	#define DEBUG(x) true
	template<typename T> void dpite(T a, T b){ return; }
#endif
#define F first
#define S second
#define SNP string::npos
#define WRC(hoge) cout << "Case #" << (hoge)+1 << ": "
#define rangej(a,b,c) ((a) <= (c) and (c) < (b))
#define rrangej(b,c) rangej(0,b,c)
template<typename T> void pite(T a, T b){ for(T ite = a; ite != b; ite++) cout << (ite == a ? "" : " ") << *ite; cout << endl;}
template<typename T> bool chmax(T& a, T b){if(a < b){a = b; return true;} return false;}
template<typename T> bool chmin(T& a, T b){if(a > b){a = b; return true;} return false;}

typedef long long int LL;
typedef unsigned long long ULL;
typedef pair<int,int> P;
typedef pair<LL,LL> LP;

void ios_init(){
	//cout.setf(ios::fixed);
	//cout.precision(12);
#ifdef LOCAL111
	return;
#endif
	ios::sync_with_stdio(false); cin.tie(0);	
}


// int stress(int n, vector<LL> a){
// 	int res = INT_MAX;
// 	int x;
// 	REP(mask, 20){
// 		int ma = 0;
// 		REP(i,n){
// 			ma = max((int)a[i]^mask, ma);
// 		}
// 		if(chmin(res,ma)) x = mask; 
// 	}
// 	return res;
// }

#define int LL

random_device rnd;

signed main()
{
	ios_init();
	int n;
	while(cin >> n){
		vector<int> a(n);
		REP(i,n) cin >> a[i];
		sort(ALL(a));
		function<int(int,int,int)> rec = [&](int sp, int ep, int kt)->int{
			int mp = ep;
			FOR(i,sp,ep){
				if((a[i]>>kt)&1){
					mp = i;
					break;
				}
			}
			int res;
			if(kt == 0){
				if(mp == ep or mp == sp){
					res = 0;
				}else{
					res = 1;
				}
			}else{
				if(mp == sp or mp == ep){
					res = rec(sp,ep,kt-1);
				}else{
					res = min((1<<kt)+rec(sp,mp,kt-1), (1<<kt)+rec(mp,ep,kt-1));
				}
			}
			return res;
		};
		int ans = rec(0,n,32);
		cout << ans << endl;
	}
	return 0;
}