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.*;
import java.io.*;
public class Main{

 static class Reader{ 
        BufferedReader br; 
        StringTokenizer st; 
  
        public Reader(){ 
            br = new BufferedReader(new InputStreamReader(System.in)); 
        } 
       
        String next(){ 
            while (st == null || !st.hasMoreElements()){ 
                try{ 
                    st = new StringTokenizer(br.readLine()); 
                } 
                catch (IOException  e){ 
                    e.printStackTrace(); 
                } 
            } 
            return st.nextToken(); 
        } 
  
        int nextInt(){ 
            return Integer.parseInt(next()); 
        } 
  
        long nextLong(){ 
            return Long.parseLong(next()); 
        } 
  
        double nextDouble(){ 
            return Double.parseDouble(next()); 
        } 
        
        String nextLine(){ 
            String str = ""; 
            try{ 
                str = br.readLine(); 
            } 
            catch (IOException e) { 
                e.printStackTrace(); 
            } 
            return str; 
        } 
    } 


  
    public static void main(final String [] args)throws IOException{
       Reader sc=new Reader();
       long n=sc.nextLong();
       String s="";

       while(n>0){
         n=n-1;
         s=(char)('a'+(n%26))+s;
         n=n/26;
       }
       System.out.println(s);


    }
}