n=int(input())
def shift(x):
    return x//2+(2**15)*(x%2)
a=[0]+list(map(int,input().split()))
if n>=16:
    print(2**16-1)
dp=[[0]*(2**16) for i in range(n+3)]
dp[0][0]=1
for i in range(1,n+1):
    for j in range(2**16):
        for iii in range(16):
            dp[i][j|a[i]]|=dp[i-1][j]
            a[i]=shift(a[i])
for j in range(2**16-1,-1,-1):
    if dp[n][j]:
        print(j)
        exit()