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.io.*;
import java.math.*;
import java.util.*;





public class Main {

    static MyScanner in = new MyScanner();
    static   PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
    int N;
    static int max = 200001;
    static int [] dr = {1,-1,0,0};
    static int [] dc={0,0,-1,1};
    static boolean [][] grid;
    static int [] bishopr = {-1,1,-1,1};
    static int [] bishopc = {1,1,-1,-1};
    static long H,W,cnt;
    public static void main(String args[]) throws IOException {
           long N = in.nextLong();
           String temp = "";
            while(N>0){
                N--;
                temp+=(char)('a'+N%26);
                N/=26;
            }
            for(int i=temp.length()-1;i>=0;i--){
                out.print(temp.charAt(i));
            }
        out.flush();
        }
       static boolean isValid (int r, int c){
           if(r>=0&&r<H&&c>=0&&c<W){
               return true;
           }
           return false;
       }
        private static void dfs(int r, int c) {
            for(int i=0;i<4;i++){
                int nr = bishopr[i] +r;
                int nc = bishopc[i]+c;
                if(isValid(nr, nc)&&!grid[nr][nc]){
                    cnt++;
                    grid[nr][nc] = true;
                    dfs(nr, nc);
                }
            }
        }

        static boolean isEven(long a) {
            return (a&1)==0;
        }
       static  void swap (int a, int b){

        int temmp = b;
        b=a;
        a = temmp;
        }
    

    public static class MyScanner {
        BufferedReader br;
        StringTokenizer st;
   
        public MyScanner() {
           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;
        }
  
     }
}