if #arg < 1 then
  print("iteration argument required")
  return
end

alpha = {"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "q", "p", "q", "r", "s", "t", "u", "v", "x", "y", "z", }
prev_pttr = ""
curr_pttr = ""
iterations = arg[1] % #alpha
for i = 1, iterations do
  curr_pttr = prev_pttr .. alpha[i] .. prev_pttr
  prev_pttr = curr_pttr
  print(curr_pttr)
end