def main():
    from sys import stdin, setrecursionlimit
    # setrecursionlimit(1000000)
    input = stdin.readline
    def iinput(): return int(input())
    def sinput(): return input().rstrip()
    def i0input(): return int(input()) - 1
    def linput(): return list(input().split())
    def liinput(): return list(map(int, input().split()))
    def miinput(): return map(int, input().split())
    def li0input(): return list(map(lambda x: int(x) - 1, input().split()))
    def mi0input(): return map(lambda x: int(x) - 1, input().split())
    INF = 1000000000000000000
    MOD = 1000000007

    def shift(x):
        return x // 2 + (1 << 15) * (x % 2)
    
    N = iinput()
    A = liinput()
    if N >= 16:
        print((1 << 16) - 1)
        return
    
    B = []
    for a in A:
        tmp = []
        for _ in [0] * 16:
            tmp.append(a)
            a = shift(a)
        B.append(tmp)
    
    ans = 0
    dp = [False] * (1 << 16)
    dp[0] = True
    for tmp in B:
        dp_nex = [False] * (1 << 16)
        for a in tmp:
            for S in range(1 << 16):
                dp_nex[S | a] |= dp[S]
        dp = dp_nex
    for S in range((1 << 16) - 1, -1, -1):
        if dp[S]:
            print(S)
            return

main()