import sys
input = sys.stdin.readline
from collections import *

N = int(input())
A = list(map(int, input().split()))

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

dp = [False]*(1<<16)
dp[0] = True

for Ai in A:
    ndp = [False]*(1<<16)
    now = Ai
    
    for _ in range(16):
        for S in range(1<<16):
            ndp[S|now] |= dp[S]
        
        now = (now%2)*(1<<15)+(now//2)
    
    dp = ndp

for i in range((1<<16)-1, -1, -1):
    if dp[i]:
        print(i)
        break