import strutils

let n = stdin.readLine.parseInt
var dic, last = ""

proc trfm(S: string): string =
  var bufStr = ""
  for s in S: bufStr.add (s.int - 'a'.int).repr
  let bufInt = bufStr.parseInt + 1
  for s in $bufInt:
    result.safeAdd ((s & "").parseInt + 'a'.int).chr

for c in ('a' .. 'y'): dic.add $c
dic.add "a"
dic = dic.replace("n", "z")

var cnt = 0
proc judge =
  cnt += 1
  if cnt >= n: echo last & "n"; quit()

var mid = "a"
while true:
  for i in 0 ..< dic.high:
    judge()
    echo dic[i] & mid & dic[i + 1]
    last = dic[i + 1] & ""
  mid = mid.trfm