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

ans = 0

if N>15:
    print(2**16-1)
    exit()

ans = 0
def shift(x):
    return (x>>1) + (1<<15) * (x&1)

dp = [[0]*16 for _ in range(N+1)]

for i in range(N):
    a = A[i]
    for j in range(16):
        for k in range(16):
            x = dp[i][k] | a
            xx = x
            z=15
            while z:
                z-=1
                x = shift(x)
                if xx<x:
                    xx = x
            dp[i+1][j] = max(dp[i+1][j], xx)
        a = shift(a)



print(max(dp[-1]))