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.*;

public class Main {
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        char alphabet[] = new char[26];

        char c = 'a';

        for(int i = 0; i < 26; i++){
            alphabet[i] = c++;
        }

        long n = sc.nextLong();

        List<Integer> list = new ArrayList<>();

        int k = 0;
        while(true){
            k++;
            long p = n % 26;

            if(p == 0) {
                list.add(26);
                if((n / 26) - 1 == 0){
                    break;
                }
                n = (n / 26) - 1;
            }else{
                list.add((int)p);
                if(n / 26 == 0){
                     break;
                }
                n /= 26;
            }
        }

        StringBuilder sb = new StringBuilder();

        for(int j = 0; j < k ; j++){
            sb.append(alphabet[list.get(j) - 1]);
        }

        System.out.println(sb.reverse());

    }
}