N = gets.to_i

memo = {}
chars = [*?a..?z]
last_chars = [*?a..?z]-[?n]
first_char = chars.sample

(N-1).times{
  last_char = last_chars.sample
  s = first_char + rand(0..18).times.map{chars.sample}*"" + last_char
  redo if memo[s]
  memo[s] = true
  puts s
  first_char = last_char
}
puts first_char + ?n