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

2.upto(N) do |n|
  s = Hash.new(0)
  s[dp[n / 2] ^ dp[(n + 1) / 2]] += 1
  s[dp[n / 3] ^ dp[(n + 1) / 3] ^ dp[(n + 2) / 3]] += 1

  res = 0
  res += 1 while s[res] != 0
  dp[n] = res
end

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