local mfl, mce = math.floor, math.ceil
local xor = bit.bxor
local n = 100
local t = {0}
for i = 2, n do
  local box = {}
  if 2 <= i and i % 2 == 0 then
    box[0] = true
  end
  if 3 <= i and i % 2 == 1 then
    local j = mfl(i / 2)
    local v = xor(t[j], t[j + 1])
    box[v] = true
  end
  if 3 <= i then
    local j = mfl(i / 3)
    if i % 3 == 0 then
      box[t[j]] = true
    elseif i % 3 == 1 then
      box[t[j + 1]] = true
    else
      box[t[j]] = true
    end
  end
  for j = 0, 1000 do
    if not box[j] then t[i] = j break end
  end
end
local a = io.read("*n")
print(t[a] == 0 and "B" or "A")