func main()
	var n: int :: cui@input().toInt(&)
	for i(1, n)
		do cui@print("a\{f(i.toStr())}" ~ (i = n ?("n\n", "a\n")))
	end for
	func f(s: []char): []char
		var res: []char :: #[^s]char
		for i(0, ^s - 1)
			do res[i] :: 'a'.offset(s[i] $ int - '0' $ int)
		end for
		ret res
	end func
end func