n = int(input())
A = list(map(int, input().split()))
if n >= 16:
    print((1 << 16) - 1)
    exit()

se = {0}
for a in A:
    nex = set()
    cand = set()
    for _ in range(16):
        cand.add(a)
        t = a & 1
        a >>= 1
        if t:
            a |= 1 << 15
    
    for a in cand:
        for b in se:
            nex.add(a | b)
    se = nex
print(max(se))