#include <bits/stdc++.h>
int max(int a, int b) { return a > b ? a : b; }
int main() {
  int m = 0, i, j, arr[105] = {0}, n;
  scanf("%d", &n);
  for (i = 0; i < n; i++) {
    scanf("%d", &arr[i]);
  }
  for (i = 0; i < n; i++) {
    int x = 0;
    for (j = i; j < n; j++) {
      x = x ^ arr[j];
      m = max(m, x);
    }
  }
  printf("%d\n", m);
  return 0;
}
