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 Java (OpenJDK 11.0.6) (judge verdict: Accepted)

import java.util.Scanner;

public class Main {

  public static void main(String[] args) {
    final Scanner scanner = new Scanner(System.in);

    long n = scanner.nextLong();

    final StringBuilder s = new StringBuilder();
    long multiplier = 26;
    int i = 0;

    long rest = n;
    while (rest > multiplier) {
      rest -= multiplier;
      multiplier *= 26;
      i++;
    }

    String result = Long.toString(rest - 1, 26)
        .replace("p", "z")
        .replace("o", "y")
        .replace("n", "x")
        .replace("m", "w")
        .replace("l", "v")
        .replace("k", "u")
        .replace("j", "t")
        .replace("i", "s")
        .replace("h", "r")
        .replace("g", "q")
        .replace("f", "p")
        .replace("e", "o")
        .replace("d", "n")
        .replace("c", "m")
        .replace("b", "l")
        .replace("a", "k")
        .replace("9", "j")
        .replace("8", "i")
        .replace("7", "h")
        .replace("6", "g")
        .replace("5", "f")
        .replace("4", "e")
        .replace("3", "d")
        .replace("2", "c")
        .replace("1", "b")
        .replace("0", "a");

    while (result.length() < i + 1) {
      result = "a" + result;
    }

    System.out.println(result);
  }
}