from collections import defaultdict, deque
from heapq import heappush, heappop
from itertools import permutations, accumulate
import sys
import math
import bisect
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def I(): return int(sys.stdin.readline())
def IR(n):
    return [I() for _ in range(n)]
def LIR(n):
    return [LI() for _ in range(n)]

sys.setrecursionlimit(1000000)
mod = 1000000007

def main():
    def shift(x):
        return (x>>1)+((x&1)<<15)
    n = I()
    a = LI()
    m = 2**16
    if n > 15:
        print(m-1)
        return
    f = [0]*m
    f[0] = 1
    for i in a:
        nf = [0]*m
        for _ in range(16):
            for x in range(m):
                if not f[x]:
                    continue
                nf[x|i] = 1
            i = shift(i)
        f = nf
    for i in reversed(range(m)):
        if f[i]:
            print(i)
            return
    return


if __name__ == "__main__":
    main()