#include <iostream>
#include <vector>
#include <climits>
#include <algorithm>
 
using namespace std;
 
int calculateMinMaxXoR(const vector<int>& A, int N) {
    vector<int> SubXor;
 
    // Iterate over all subarrays of length at least 2
    for (int i = 0; i < N; ++i) {
        int minVal = INT_MAX;
        int maxVal = INT_MIN;
        for (int j = i; j < N; ++j) {
            minVal = min(minVal, A[j]);
            maxVal = max(maxVal, A[j]);
            if (j - i + 1 >= 2) {
                SubXor.push_back(minVal ^ maxVal);
            }
        }
    }
 
    // Calculate the final MinMaxXoR
    int MinMaxXoR = 0;
    for (int value : SubXor) {
        MinMaxXoR ^= value;
    }
 
    return MinMaxXoR;
}
 
int main() {
    int N;
    cin >> N;
    vector<int> A(N);
    for (int i = 0; i < N; ++i) {
        cin >> A[i];
    }
 
    int result = calculateMinMaxXoR(A, N);
    cout << result << endl;
 
    return 0;
}