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.Scanner;

public class Main {
	
	public static void main(String[] args){
		
		Scanner scan = new Scanner(System.in);
		long n = scan.nextLong();
		scan.close();
		
		// 0がaになり、1大きい数が渡されるけど、アルファベットだけの26進数にしてね
		System.out.println(convertOriginalShinsuStr(n, 'a', 1, 26));
		
	}
	
	/**
	 * 10進数をオリジナル進数(アルファベット)文字列に変換
	 * @param dNum 変換する10進数
	 * @param origin 10進数の0をオリジナル進数で変換した後の文字
	 * @param offset オリジナル変数の0に何を足せば10進数の0になるか？
	 * @param baseNumber 何進数に変換するの
	 * @return オリジナル進数(アルファベット)文字列
	 */
	public static String convertOriginalShinsuStr(
			long dNum, final char origin, final int offset, final int baseNumber) {
		
		String ret = "";
		
		while(dNum > 0) {
			// char型はintと足し算できる
			ret = String.valueOf((char)(origin + (dNum - offset) % baseNumber )) + ret;
			// int型の割り算で小数点以下は切り捨てられることを利用して次の位へ
			dNum /= (baseNumber + 1); 
		}
		
		return ret;
		
	}

}