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()
    A.sort(reverse=True)

    ans = 0
    for a in A:
        tmp = ans | a
        for _ in [0] * 20:
            a = shift(a)
            tmp = max(tmp, ans|a)
        ans = tmp

    print(ans)

main()