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();
		String[] list = {"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"};
		int exp = 0;
		String name = "";
		
		long pow = 0;
		for(int i=1;i<=11;i++) {
			if(pow < n) {
				pow = (long) (pow + Math.pow(26, i));
			}else {
				exp = i-1;
				break;
			}
		}
		
		long s = 0;
		String[] namelist = new String[exp];
		for(int j=0;j<exp;j++) {
			if(n > 26) {
				s = n % 26;
				n = n / 26;
				if(s == 0) {
					s = 26;
					n = n - 1;
				}
				namelist[j] = list[(int) (s-1)];
			}else {
				namelist[j] = list[(int) (n-1)];
			}
		}
		for(int k=exp-1;k>=0;k--) {
			name = name + namelist[k];
		}
		System.out.println(name);
	}

}