Problem:
Score : 300 points

Problem Statement

1000000000000001 dogs suddenly appeared under the roof of Roger's house, all of which he decided to keep. The dogs had been numbered 1 through 1000000000000001, but he gave them new names, as follows:

the dogs numbered 1,2,\cdots,26 were respectively given the names a, b, ..., z;

the dogs numbered 27,28,29,\cdots,701,702 were respectively given the names aa, ab, ac, ..., zy, zz;

the dogs numbered 703,704,705,\cdots,18277,18278 were respectively given the names aaa, aab, aac, ..., zzy, zzz;

the dogs numbered 18279,18280,18281,\cdots,475253,475254 were respectively given the names aaaa, aaab, aaac, ..., zzzy, zzzz;

the dogs numbered 475255,475256,\cdots were respectively given the names aaaaa, aaaab, ...;

and so on.

To sum it up, the dogs numbered 1, 2, \cdots were respectively given the following names:

a, b, ..., z, aa, ab, ..., az, ba, bb, ..., bz, ..., za, zb, ..., zz, aaa, aab, ..., aaz, aba, abb, ..., abz, ..., zzz, aaaa, ...

Now, Roger asks you:

"What is the name for the dog numbered N?"

Constraints

N is an integer.

1 \leq N \leq 1000000000000001

Input

Input is given from Standard Input in the following format:

N

Output

Print the answer to Roger's question as a string consisting of lowercase English letters.

Sample Input 1

2

Sample Output 1

b

Sample Input 2

27

Sample Output 2

aa

Sample Input 3

123456789

Sample Output 3

jjddja

Solution in Scala (2.13.1) (judge verdict: Wrong Answer)

object Main extends App {
	val pw = new java.io.PrintWriter(System.out)

	@scala.annotation.tailrec
	def loop(start: Int, end: Int)(f: Int => Unit): Unit =
		if (start < end) {
			f(start)
			loop(start + 1, end)(f)
		}

	def num2alp(n: Int): Char = (n + 'a'.toInt - 1).toChar

	@scala.annotation.tailrec
	def posnot26(n: Long, now: Seq[Char] = Seq.empty): Seq[Char] =
		if (n <= 0) now
		else posnot26(n / 26L, num2alp((n % 26L).toInt) +: now)

	pw.println(posnot26(Scanner.nextLong).mkString)
	pw.flush()
}

object Scanner {
	private val buf = new Array[Byte](1024); private var ptr = 0; private var len = 0

	@inline private def isPrintableChar(c: Int): Boolean = 33 <= c && c <= 126
	@inline private def hasNextByte(): Boolean = if (ptr >= len) { ptr = 0; len = System.in.read(buf); len > 0 } else true
	@inline private def hasNext(): Boolean = {
		while (hasNextByte() && !isPrintableChar(buf(ptr))) ptr += 1
		hasNextByte()
	}
	@inline private def readByte(): Byte = if (hasNextByte()) { val res = buf(ptr); ptr += 1; res } else -1

	def next(): String = {
		if(!hasNext()) ???
		val sb = new StringBuilder; var b = readByte()
		while (isPrintableChar(b)) { sb.append(b.toChar); b = readByte() }
		sb.toString
	}

	def nextInt(): Int = {
		val n = nextLong()
		if (n < Int.MinValue || Int.MaxValue < n) ???
		n.toInt
	}

	def nextLong(): Long = {
		if(!hasNext()) ???
		var minus = false; var b = readByte()
		if (b == '-') { minus = true; b = readByte() }

		@scala.annotation.tailrec
		def go (b: Byte, n: Long = 0): Long = if ('0' <= b && b <= '9') go(readByte(), n * 10 + b - '0') else if (minus) -n else n

		go(b)
	}

	def nextDouble(): Double = next().toDouble
}