N = gets.to_i
dp = Array.new(101, 0)

2.upto(N) do |n|
  if n % 2 == 0
    dp[n] = 1
  else
    if dp[n / 2] ^ dp[(n + 1) / 2] == 0
      dp[n] += 1
    end

    if dp[n / 3] ^ dp[(n + 1) / 3] ^ dp[(n + 2) / 3] == 0
      dp[n] += 1
    end
  end
end

puts (dp[N] != 0) ? 'A' : 'B'