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

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

C = 1 << 16
def shift(x):
    return (x >> 1) + (x & 1) * (1 << 15)
dp = [0] * C
dp[0] = 1
for a in A:
    nx = [0] * C
    for i in range(C):
        if dp[i]:
            for _ in range(16):
                nx[i | a] = 1
                a = shift(a)
    dp = nx
for i in range(C - 1,-1,-1):
    if dp[i]:
        print(i)
        exit()