#include <bits/stdc++.h>
using namespace std;
const int maxn = 110;
int a[maxn], n, f[maxn][maxn], ans;
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%d", &a[i]);
    f[i][i] = a[i];
    ans = max(ans, f[i][i]);
  }
  for (int i = 1; i <= n; i++) {
    for (int j = i + 1; j <= n; j++) {
      f[i][j] = f[i][j - 1] ^ a[j];
      ans = max(ans, f[i][j]);
    }
  }
  printf("%d\n", ans);
  return 0;
}
