// Standard I/O #include #include #include // Standard Library #include #include #include #include // Template Class #include #include #include #include #include #include #include #include // Container Control #include using namespace std; #define rep( i, n ) for( int i = 0; i < n; ++i ) #define irep( i, n ) for( int i = n-1; i >= 0; --i ) #define reep( i, s, n ) for ( int i = s; i < n; ++i ) #define ireep( i, n, s ) for ( int i = n-1; i >= s; --i ) #define foreach(itr, x) for( typeof(x.begin()) itr = x.begin(); itr != x.end(); ++itr) #define mp( a, b ) make_pair( a, b ) #define pb( a ) push_back( a ) #define all( v ) v.begin(), v.end() #define fs first #define sc second #define vc vector // for visualizer.html double SCALE = 1.0; double OFFSET_X = 0.0; double OFFSET_Y = 0.0; #define LINE(x,y,a,b) cerr << "line(" << SCALE*(x) + OFFSET_X << "," \ << SCALE*(y) + OFFSET_Y << "," \ << SCALE*(a) + OFFSET_X << "," \ << SCALE*(b) + OFFSET_Y << ")" << endl; #define CIRCLE(x,y,r) cerr << "circle(" << SCALE*(x) + OFFSET_X << "," \ << SCALE*(y) + OFFSET_Y << "," \ << SCALE*(r) << ")" << endl; typedef long long ll; typedef complex Point; typedef pair pii; typedef pair ipii; typedef vector vi; typedef vector vd; typedef vector< vector > vii; typedef vector< vector > vdd; typedef vector::iterator vi_itr; const int IINF = 1 << 28; const double INF = 1e30; const double EPS = 1e-10; const double PI = acos(-1.0); // Direction : L U R D const int dx[] = { -1, 0, 1, 0}; const int dy[] = { 0, -1, 0, 1 }; int N; ll a[100000]; ll solve ( int d, ll x ) { if( d == -1 ){ ll ans = 0; rep(i, N) ans = max(ans, a[i]^x); return ans; } ll num = 0; rep(i, N) if( (a[i] & (1ll << d)) != 0 ) ++num; if( num == N ) return solve(d-1, x | (1ll << d)); else if( num == 0 ) return solve(d-1, x); else return min(solve(d-1, x), solve(d-1, x | (1ll << d))); } int main() { cin >> N; rep(i, N) cin >> a[i]; cout << solve(31, 0) << endl; }