func main()
	var n: int :: cui@inputInt()
	var a: []int :: #[10]int
	for i(1, 9)
		do a[i] :: a[i - 1] + 26 ^ i
		if(n < a[i])
			do n :- a[i - 1]
			var s: []char :: ""
			for j(0, i - 1)
				do s :~ ['A'.offset(n % 26)]
				do n :/ 26
			end for
			do s.reverse()
			do cui@print("\{s}\n")
			ret
		end if
	end for
end func