def shift(x):
    return x//2 + (1 << 15) * (x % 2)
n = int(input())
a =list(map(int,input().split()))
dp = [0] * (1<<16)
dp[0] = 1
for i in range(min(15,n)):
    aa = a[i]
    n_dp = [0] * (1<<16)
    for j in range(14):
        for k in range(1<<16):
            if dp[k]:
                n_dp[k|aa] = 1
        aa = shift(aa)
    dp = n_dp
import sys
for i in range((1<<16)-1,-1,-1):
#     print(i)
    if dp[i]:sys.exit(print(i))