N = gets.to_i
$str_memo = %w(a b c d e f g h i j k)
# def rec(array)
#   size = array.size
#   if size == N
#     puts array.join("")
#     return
#   end
#   (size + 1).times do |i|
#     rec(array + [$str_memo[i]])
#   end
# end
# rec([])

puts "aaa"
puts "aab"
puts "aba"
puts "abb"
puts "abc"
