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: Wrong Answer)

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    // 何匹目の犬であるか
    Long n = sc.nextLong();
    List<String> anStrings = new ArrayList<>();
    List<String> list = new ArrayList<>();
    list.add("z");
    list.add("a");
    list.add("b");
    list.add("c");
    list.add("d");
    list.add("e");
    list.add("f");
    list.add("g");
    list.add("h");
    list.add("i");
    list.add("j");
    list.add("k");
    list.add("l");
    list.add("m");
    list.add("n");
    list.add("o");
    list.add("p");
    list.add("q");
    list.add("r");
    list.add("s");
    list.add("t");
    list.add("u");
    list.add("v");
    list.add("w");
    list.add("x");
    list.add("y");
    int cnt = 0;
    boolean flg=false;
    while(true) {
        if(n>=26) {
            n = n - cnt;
            if(n==26) flg=true;
            int num = (int) (n % 26);
            anStrings.add(list.get(num));
            n /= 26;
            if(num==0)
                cnt=1;
            if(flg) break;
        }
        else {
            int num = (int) (n % 26);
            anStrings.add(list.get(num));
            break;
        }
    }
    for(int i=anStrings.size()-1;i>=0;i--) {
        System.out.print(anStrings.get(i));
    }
    System.out.println("");
  }
}