n = gets.to_i

if n <= 2
  p -1
elsif n == 3
  puts "aab"
  puts "c.b"
  puts "cdd"
else
  s = "." * (n - 4) + "\n"
  printf("aacd" + "." * (n - 4) + "\n")
  printf("bbcd" + "." * (n - 4) + "\n")
  printf("efgg" + "." * (n - 4) + "\n")
  printf("efhh" + "." * (n - 4) + "\n")

  (n-4).times do
    printf("." * (n) + "\n")
  end
end

