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 1.8.0) (judge verdict: Wrong Answer)

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		// 読み込み
		Scanner sc = new Scanner(System.in);
		long N = sc.nextLong();
		
		long div = N;
		int mod = 0;
		
		List<Integer> list = new ArrayList<>();
		
		while(true) {
			mod = (int) (div % 26);
			div = div / 26;
			
			list.add(mod);
			
			if(div == 0) {
				break;
			}
		}
		
		Collections.reverse(list);
		
		for(int i : list) {
			
			switch(i) {
			case 1 :
				System.out.print("a");
				break;
			case 2 :
				System.out.print("b");
				break;
			case 3 :
				System.out.print("c");
				break;
			case 4 :
				System.out.print("d");
				break;
			case 5 :
				System.out.print("e");
				break;
			case 6 :
				System.out.print("f");
				break;
			case 7 :
				System.out.print("g");
				break;
			case 8 :
				System.out.print("h");
				break;
			case 9 :
				System.out.print("i");
				break;
			case 10 :
				System.out.print("j");
				break;
			case 11 :
				System.out.print("k");
				break;
			case 12 :
				System.out.print("l");
				break;
			case 13 :
				System.out.print("m");
				break;
			case 14 :
				System.out.print("n");
				break;
			case 15 :
				System.out.print("o");
				break;
			case 16 :
				System.out.print("p");
				break;
			case 17 :
				System.out.print("q");
				break;
			case 18 :
				System.out.print("r");
				break;
			case 19 :
				System.out.print("s");
				break;
			case 20 :
				System.out.print("t");
				break;
			case 21 :
				System.out.print("u");
				break;
			case 22 :
				System.out.print("v");
				break;
			case 23 :
				System.out.print("w");
				break;
			case 24 :
				System.out.print("x");
				break;
			case 25 :
				System.out.print("y");
				break;
			case 26 :
				System.out.print("z");
				break;					
			}
		}
	}
}