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: Accepted)

import java.util.Scanner;
import java.util.Stack;

public class Main {

	public static void main(String[] args) {
	    Scanner sc = new Scanner(System.in);
        long N = sc.nextLong();
        String[] alphabet = {"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"};
        Stack<String> stack = new Stack<String>();

        while(N>26) {
            long remain = N%26;
            if(remain==0) {
                remain=26;
            }
            stack.add(alphabet[(int)(remain-1)]);
            N-=remain;
            N/=26;
        }
        long last_remain = N%26;
        if(last_remain == 0) {
            last_remain=26;
        }
        stack.add(alphabet[(int)(last_remain-1)]);

        while(!stack.isEmpty()) {
            System.out.print(stack.pop());
        }

	}

}