#include <iostream>
#include <vector>
#include <list>
#include <algorithm>
#include <string>
#include <sstream>
#include <stack>
#include <iomanip>
#include <numeric>
#include <queue>
#include <climits>
#include <set>
#include <complex>
#include <cmath>
#include <cstring>
#include <map>
using namespace std;
using ll = long long;
#define MOD 1000000007
#define INF 1LL << 59
using ld = long double;

int arr[15];
int N;
int maxV = 0;

void dfs(int d, stack<int> st, bool used[15])
{
    if (d == N)
    {
        int sum = 0;
        while (st.size())
        {
            sum = sum ^ st.top();
            st.pop();
        }
        maxV = max(maxV, sum);
        return;
    }

    for (int i = 0; i < N; ++i)
    {
        if (!used[i])
        {
            used[i] = true;
            if (d % 2 == 1)
            {
                int n = st.top();
                st.pop();
                st.push(n + arr[i]);

                dfs(d + 1, st, used);

                st.pop();
                st.push(n);
            }
            else
            {
                st.push(arr[i]);
                dfs(d + 1, st, used);
                st.pop();
            }
            used[i] = false;
        }
    }
}
int main()
{
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    //cout << fixed << setprecision(5);

    cin >> N;
    for (int i = 0; i < N; ++i)
        cin >> arr[i];

    bool used[15];
    for (int i = 0; i < N; ++i)
        used[i] = false;

    stack<int> st;
    dfs(0, st, used);

    cout << maxV << endl;
    return 0;
}