#include <bits/stdc++.h>
using namespace std;
 
int main()
{
	int N;
	cin >> N;
	vector<long long> A( N );
	for( int i = 0; i < N; i++ ) {
		cin >> A[i];
	}

	sort( A.begin(), A.end() );
	long long ans = 0;
	do {
		long long X = 0;
		for( int i = 0; i < N - 1; i++ ) {
			X ^= A[i] ^ A[i + 1];
		}
		ans = max( ans, X );
	} while( next_permutation( A.begin(), A.end() ) );

	cout << ans << endl;
}