import sys
#input = sys.stdin.readline
#input = sys.stdin.buffer.readline #文字列はダメ
#sys.setrecursionlimit(1000000)
import math
#import bisect
#import itertools
#import random
#from heapq import heapify, heappop, heappush
from collections import defaultdict 
from collections import deque
#import copy #DeepCopy: hoge = [_[:] for _ in hogehoge]
#from functools import lru_cache
#@lru_cache(maxsize=None)
#MOD = pow(10,9) + 7
#MOD = 998244353
#dx = [1,0,-1,0]
#dy = [0,1,0,-1]
#dx8 = [1,1,0,-1,-1,-1,0,1]
#dy8 = [0,1,1,1,0,-1,-1,-1]

def shift(x):
    return x//2 + pow(2,15) * (x%2)

def main():
    N = int(input())
    A = list(map(int,input().split()))

    if N >= 15:
        ans = 1 << 16
        print(ans-1);exit()

    M = 1 << 16
    # dp[mask]: maskの値となるかどうか 
    dp = [0]*M
    dp[0] = 1

    for a in A:
        p = [0]*M
        p,dp = dp,p
        for x in range(16):
            a = shift(a)
            for mask in range(M):
                dp[mask|a] |= p[mask]
    
    for i in reversed(range(M)):
        if dp[i] == 1:
            print(i)
            exit()



if __name__ == '__main__':
    main()