def shift(x):
    return ((x % 2) << 15) + x//2

N =int(input())
A = list(map(int, input().split()))
if N >= 16:
    print(2 ** 16 - 1)
    exit()
            
pre = [0] * (1 << 16)
pre[0] = 1 
for i in range(N):
    dp = [0] * (1 << 16)
    v = A[i]
    for s in range(1 << 16):
        for j in range(16):
            dp[s|v] |= pre[s]
            v = shift(v)
    pre, dp = dp, pre

for i in range(2 ** 16 - 1, -1, -1):
    if pre[i]:
        print(i)
        break