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.*;

public class Main {

    public static void main(String args[]) {

        // 入力
        Scanner sc = new Scanner(System.in);
        long n = Long.parseLong(sc.next());
        sc.close();

        // 主処理
        char[] base26 = Long.toString(n, 26).toCharArray();
        int moveUp = 0;
        Deque<Integer> indexQueue = new ArrayDeque<>();
        for (int i = base26.length - 1; 0 <= i; i--) {
            char c = (char) ((int) base26[i] + moveUp);
            if (c == '0') {
                indexQueue.add(26);
                moveUp = -1;
                continue;
            }
            int minusIndex = String.valueOf(c).matches("[1-9]") ? 48 : 87;
            int index = (int) c + moveUp - minusIndex;
            indexQueue.add(index);
            moveUp = 0;
        }

        Deque<String> dq = new ArrayDeque<>();
        while (!indexQueue.isEmpty()) {
            int index = indexQueue.pollFirst();
            if (index != 0) {
                String str = String.valueOf((char) ((int) 'a' + index - 1));
                dq.addFirst(str);
            }
        }

        String result = String.join("", dq);

        // 出力
        System.out.println(result);
    }
}