#include <bits/stdc++.h>   using namespace std;   int j, i, a, b, c, k, d, e, f[1005], n, mi, ma;   int main() {     cin >> n;     for (i = 0; i < n; i++) {       cin >> f[i];       ma = max(f[i], ma);     }     for (i = 0; i < n - 1; i++)       for (j = i + 1; j < n; j++) {         c = 0;         for (k = i; k <= j; k++) c = f[k] ^ c;         ma = max(ma, c);       }     cout << ma;     return 0;   }   