from time import time
from random import shuffle

stime = time()
N = int(input())
A = list(map(int, input().split()))
if N >= 15:
    print(2**16-1)
    exit()
ans = 0
while stime+1.7 > time():
    v = 0
    nv = 0
    shuffle(A)
    for a in A:
        for i in range(16):
            nv = max(v|a,nv)
            a = a//2+2**15*(a%2)
        v = nv

    ans = max(v,ans)
print(ans)