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) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);

		long n = sc.nextLong() - 1;
		int b = 0;
		int[] c = new int[b];
		int[] c2 = new int[b];
		while(n >= 0) {
			c = new int[b];
			c = c2;
			c2 = new int[b+1];
			System.arraycopy(c, 0, c2, 0, b);

			c2[b] = (int)n % 26;
			n = n/26 - 1;
			b++;
		}

		for(int i=c2.length-1; i>=0; i--) {
			isAlfabet(c2[i]);
		}
	}
	private static void isAlfabet(long num) {
		String[] s = {"a","b","c","d","e","f","g","h","i","j","k","l","m",
				"n","o","p","q","r","s","t","u","v","w","x","y","z"};
		if(num > -1) {
			System.out.print(s[(int)num]);
			//System.out.println(num);
		}
	}
}