#include <bits/stdc++.h>
using namespace std;
inline void read(int &x) {
  char c = getchar();
  int w = 1;
  x = 0;
  while (!isdigit(c)) (c == '-') && (w = -w), c = getchar();
  while (isdigit(c)) x = (x << 1) + (x << 3) + (c ^ 48), c = getchar();
  x *= w;
}
inline void write(int x) {
  if (x < 0) putchar('-'), x = -x;
  if (x > 9) write(x / 10);
  putchar(x % 10);
}
int a[100], n, i, x, j;
int main() {
  read(n);
  a[0] = 0;
  read(a[1]);
  int maxx = -214748348;
  for (register int i = 2; i <= n; i++) {
    read(x);
    a[i] = a[i - 1] ^ x;
  }
  for (register int i = 1; i <= n; i++) {
    for (register int j = i; j <= n; j++) {
      maxx = max(maxx, a[j] ^ a[i - 1]);
    }
  }
  printf("%d", maxx);
  return 0;
}
