from typing import List, Tuple, Optional
import sys
import itertools
import heapq
import bisect
from collections import deque, defaultdict
from functools import lru_cache, cmp_to_key

input = sys.stdin.readline

# for AtCoder Easy test
if __file__ != 'prog.py':
    sys.setrecursionlimit(10 ** 6)


def readints(): return map(int, input().split())
def readlist(): return list(readints())
def readstr(): return input().rstrip()


N = int(input())
A = readlist()

if N > 15:
    print((1 << 16) - 1)
    exit()

dp = [False] * (1 << 16)
dp[0] = True
for a in A:
    ndp = [False] * (1 << 16)
    for j in range(1 << 16):
        if dp[j] is False:
            continue
        acc = a
        for k in range(16):
            ndp[j | acc] = True
            if acc & 1:
                acc = (acc >> 1) + (1 << 15)
            else:
                acc = (acc >> 1)
    dp = ndp

for s in range(1 << 16)[::-1]:
    if dp[s] is True:
        print(s)
        break