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

def f(x):
    return x//2+(1<<15)*(x&1)
if N>=16:
    exit(print((1<<16)-1))
else:
    dp = [[False]*(1<<16) for _ in range(N+1)]
    dp[0][0] = True
    for i in range(1,N+1):
        for j in range(1<<16):
            if dp[i-1][j]:
                for k in range(16):
                    dp[i][j|A[i-1]] = True
                    A[i-1] = f(A[i-1])
    for i in range((1<<16)-1,-1,-1):
        if dp[-1][i]:
            print(i)
            exit()