N = gets.to_i
A = gets.split.map(&:to_i)

def shift(x)
  x / 2 + 2 ** 15 * (x % 2)
end

if N >= 16
  puts 2 ** 16 - 1
  exit
end

L = 2 ** 16 
dp = Array.new(N + 1) { Array.new(L, false) }
dp[0][0] = true

1.upto(N) do |i|
  L.times do |j|
    next if not dp[i - 1][j]
    a = A[i - 1]

    16.times do
      nv = j | a
      dp[i][nv] |= dp[i - 1][j]
      a = shift(a)
    end
  end
end

pp dp[N].rindex(true)