#include <bits/stdc++.h>
int compare(const void* a, const void* b) {
  return *(long long*)a - *(long long*)b;
}
long long a[200];
int main() {
  long long t, max = 0, s = 0;
  scanf("%lld", &t);
  for (long long i = 1; i <= t; i++) {
    scanf("%lld", &a[i]);
  }
  for (long long i = 1; i <= t; i++) {
    s = a[i];
    if (s > max) {
      max = s;
    }
    for (long long j = i + 1; j <= t; j++) {
      s = a[j] ^ s;
      if (s > max) {
        max = s;
      }
    }
    if (s > max) {
      max = s;
    }
  }
  printf("%lld", max);
  return 0;
}
