import java.util.*;
import java.util.Scanner;
import java.io.*;
import java.io.BufferedReader; 
import java.io.IOException; 
import java.io.InputStreamReader; 
import java.util.Scanner; 
import java.util.StringTokenizer; 
 
public class Main
{
    static class FastReader 
    { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastReader() 
        { 
            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 (String[] args) 
	{
        //code by sushant kumar
        FastReader in=new FastReader();
        long n=in.nextLong();
       
        String s="";
        

        while(n>0)
        {
   
            long d=n%26;
           
            char ch=' ';
            if(d!=0)
                ch=(char)((int)d+96);
            else
                ch='z';
            
            s=ch+s;
            if(n%26!=0)
                n/=26;
            else

                n=n/26-1;
            
        }
       

        System.out.println(s);
    }
} import java.util.*; util.* java import java.util.Scanner; Scanner java.util import java.io.*; io.* java import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.Scanner; Scanner java.util import java.util.StringTokenizer; StringTokenizer java.util public class Main
{
    static class FastReader 
    { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastReader() 
        { 
            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 (String[] args) 
	{
        //code by sushant kumar
        FastReader in=new FastReader();
        long n=in.nextLong();
       
        String s="";
        

        while(n>0)
        {
   
            long d=n%26;
           
            char ch=' ';
            if(d!=0)
                ch=(char)((int)d+96);
            else
                ch='z';
            
            s=ch+s;
            if(n%26!=0)
                n/=26;
            else

                n=n/26-1;
            
        }
       

        System.out.println(s);
    }
} Main public static void main (String[] args) 
	{
        //code by sushant kumar
        FastReader in=new FastReader();
        long n=in.nextLong();
       
        String s="";
        

        while(n>0)
        {
   
            long d=n%26;
           
            char ch=' ';
            if(d!=0)
                ch=(char)((int)d+96);
            else
                ch='z';
            
            s=ch+s;
            if(n%26!=0)
                n/=26;
            else

                n=n/26-1;
            
        }
       

        System.out.println(s);
    } main {
        //code by sushant kumar
        FastReader in=new FastReader();
        long n=in.nextLong();
       
        String s="";
        

        while(n>0)
        {
   
            long d=n%26;
           
            char ch=' ';
            if(d!=0)
                ch=(char)((int)d+96);
            else
                ch='z';
            
            s=ch+s;
            if(n%26!=0)
                n/=26;
            else

                n=n/26-1;
            
        }
       

        System.out.println(s);
    } FastReader in=new FastReader(); in new FastReader() long n=in.nextLong(); n in.nextLong() in.nextLong in String s=""; s "" while(n>0)
        {
   
            long d=n%26;
           
            char ch=' ';
            if(d!=0)
                ch=(char)((int)d+96);
            else
                ch='z';
            
            s=ch+s;
            if(n%26!=0)
                n/=26;
            else

                n=n/26-1;
            
        } n>0 n 0 {
   
            long d=n%26;
           
            char ch=' ';
            if(d!=0)
                ch=(char)((int)d+96);
            else
                ch='z';
            
            s=ch+s;
            if(n%26!=0)
                n/=26;
            else

                n=n/26-1;
            
        } long d=n%26; d n%26 n 26 char ch=' '; ch ' ' if(d!=0)
                ch=(char)((int)d+96);
            else
                ch='z'; d!=0 d 0 ch=(char)((int)d+96) ch (char)((int)d+96) (int)d 96 ch='z' ch 'z' s=ch+s s ch+s ch s if(n%26!=0)
                n/=26;
            else

                n=n/26-1; n%26!=0 n%26 n 26 0 n/=26 n 26 n=n/26-1 n n/26-1 n/26 n 26 1 System.out.println(s) System.out.println System.out System System.out s String[] args args static class FastReader 
    { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastReader() 
        { 
            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; 
        } 
    } FastReader BufferedReader br; br StringTokenizer st; st public FastReader() 
        { 
            br = new BufferedReader(new
                     InputStreamReader(System.in)); 
        } FastReader { 
            br = new BufferedReader(new
                     InputStreamReader(System.in)); 
        } br = new BufferedReader(new
                     InputStreamReader(System.in)) 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(); 
        } next { 
            while (st == null || !st.hasMoreElements()) 
            { 
                try
                { 
                    st = new StringTokenizer(br.readLine()); 
                } 
                catch (IOException  e) 
                { 
                    e.printStackTrace(); 
                } 
            } 
            return st.nextToken(); 
        } while (st == null || !st.hasMoreElements()) 
            { 
                try
                { 
                    st = new StringTokenizer(br.readLine()); 
                } 
                catch (IOException  e) 
                { 
                    e.printStackTrace(); 
                } 
            } st == null || !st.hasMoreElements() st == null st null !st.hasMoreElements() st.hasMoreElements() st.hasMoreElements st { 
                try
                { 
                    st = new StringTokenizer(br.readLine()); 
                } 
                catch (IOException  e) 
                { 
                    e.printStackTrace(); 
                } 
            } try
                { 
                    st = new StringTokenizer(br.readLine()); 
                } 
                catch (IOException  e) 
                { 
                    e.printStackTrace(); 
                } catch (IOException  e) 
                { 
                    e.printStackTrace(); 
                } IOException  e { 
                    e.printStackTrace(); 
                } e.printStackTrace() e.printStackTrace e { 
                    st = new StringTokenizer(br.readLine()); 
                } st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st int nextInt() 
        { 
            return Integer.parseInt(next()); 
        } nextInt { 
            return Integer.parseInt(next()); 
        } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next long nextLong() 
        { 
            return Long.parseLong(next()); 
        } nextLong { 
            return Long.parseLong(next()); 
        } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next double nextDouble() 
        { 
            return Double.parseDouble(next()); 
        } nextDouble { 
            return Double.parseDouble(next()); 
        } return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next String nextLine() 
        { 
            String str = ""; 
            try
            { 
                str = br.readLine(); 
            } 
            catch (IOException e) 
            { 
                e.printStackTrace(); 
            } 
            return str; 
        } nextLine { 
            String str = ""; 
            try
            { 
                str = br.readLine(); 
            } 
            catch (IOException e) 
            { 
                e.printStackTrace(); 
            } 
            return str; 
        } String str = ""; str "" try
            { 
                str = br.readLine(); 
            } 
            catch (IOException e) 
            { 
                e.printStackTrace(); 
            } catch (IOException e) 
            { 
                e.printStackTrace(); 
            } IOException e { 
                e.printStackTrace(); 
            } e.printStackTrace() e.printStackTrace e { 
                str = br.readLine(); 
            } str = br.readLine() str br.readLine() br.readLine br return str; str public class Main
{
    static class FastReader 
    { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastReader() 
        { 
            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 (String[] args) 
	{
        //code by sushant kumar
        FastReader in=new FastReader();
        long n=in.nextLong();
       
        String s="";
        

        while(n>0)
        {
   
            long d=n%26;
           
            char ch=' ';
            if(d!=0)
                ch=(char)((int)d+96);
            else
                ch='z';
            
            s=ch+s;
            if(n%26!=0)
                n/=26;
            else

                n=n/26-1;
            
        }
       

        System.out.println(s);
    }
} public class Main
{
    static class FastReader 
    { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastReader() 
        { 
            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 (String[] args) 
	{
        //code by sushant kumar
        FastReader in=new FastReader();
        long n=in.nextLong();
       
        String s="";
        

        while(n>0)
        {
   
            long d=n%26;
           
            char ch=' ';
            if(d!=0)
                ch=(char)((int)d+96);
            else
                ch='z';
            
            s=ch+s;
            if(n%26!=0)
                n/=26;
            else

                n=n/26-1;
            
        }
       

        System.out.println(s);
    }
} Main
import java.util.*;
import java.util.Scanner;
import java.io.*;
import java.io.BufferedReader; 
import java.io.IOException; 
import java.io.InputStreamReader; 
import java.util.Scanner; 
import java.util.StringTokenizer; 
 
public class Main
{
    static class FastReader 
    { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastReader() 
        { 
            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 (String[] args) 
	{
        //code by sushant kumar
        FastReader in=new FastReader();
        long n=in.nextLong();
       
        String s="";
        

        while(n>0)
        {
   
            long d=n%26;
           
            char ch=' ';
            if(d!=0)
                ch=(char)((int)d+96);
            else
                ch='z';
            
            s=ch+s;
            if(n%26!=0)
                n/=26;
            else

                n=n/26-1;
            
        }
       

        System.out.println(s);
    }
}