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

if n > 16:
    print(2**16-1)
    exit()


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

dp[0] = 1

for a in A:
    for i in range(1<<16)[::-1]:
        if dp[i] == 0:
            continue
        base = a
        # print("base",base)
        for j in range(16):
            dp[i|base] = 1
            base =  (1<<15)*(base%2) + base//2 
            # print(base)
for i in range(1<<16)[::-1]:
    if dp[i]:
        print(i)
        exit()