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.*;
import java.math.BigInteger;

public class Main{
public static void main(String[] args) {
    Scanner scan = new Scanner(System.in);
    BigInteger a = new BigInteger(scan.next());
    scan.close();

    int[] alpha = new int[26];
    int cnt = 0;
    int tmp;
    BigInteger bi26 = new BigInteger("26");
    BigInteger bi1 = new BigInteger("1");
    BigInteger bi0 = new BigInteger("0");
    while(a.compareTo(bi0) == 1) {
        BigInteger rem = a.remainder(bi26);
        String strrem = rem.toString();
        tmp = Integer.parseInt(strrem);
        if (tmp == 0) {
            alpha[cnt] = 26;
            a = a.divide(bi26);
            a = a.subtract(bi1);
        } else {
            alpha[cnt] = tmp;
            a = a.divide(bi26);
        }
        cnt++;
    }
//for(int i=0;i<cnt;i++) {
//    System.out.println(alpha[i]);
//}

    StringBuilder sb = new StringBuilder();
    for(int i=0;i<cnt;i++) {
        byte[] ascii = new byte[cnt];
        ascii[i] = (byte)(97 + alpha[i] - 1);
        String outstr = new String(ascii);
        sb.insert(0,outstr);
    }

    System.out.println(sb);

}
}