# n = int(input())
# arr = list(map(int, input().split()))
# otvet = sum(arr)
# for i in arr:
#     otvet |= i
# print(otvet)


n = int(input())
t = n ** 2

a = 0
arr = list(map(int, input().split()))
otvet = sum(arr)


for i in range(n):
    for j in range(n - 1):
        a = arr[i] + arr[j]
        otvet |= i

for i in arr:
    otvet |= i

print(otvet)