import java.util.*;
import java.io.*;
public class Main
{
    public static void main(String ars[])throws Exception
    {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw=new PrintWriter(System.out);
        //String str[]=br.readLine().split(" ");
        long n=Long.parseLong(br.readLine());
        //int k=Integer.parseInt(str[1]);
        StringBuffer sb=new StringBuffer();
        while(n>0)
        {
            int mod=(int)((n-1)%26);
            sb.append((char)(mod+97));
            n=(n-1)/26;
        }
        sb.reverse();
        pw.println(sb.toString());
        pw.flush();
        pw.close();
    }
} import java.util.*; util.* java import java.io.*; io.* java public class Main
{
    public static void main(String ars[])throws Exception
    {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw=new PrintWriter(System.out);
        //String str[]=br.readLine().split(" ");
        long n=Long.parseLong(br.readLine());
        //int k=Integer.parseInt(str[1]);
        StringBuffer sb=new StringBuffer();
        while(n>0)
        {
            int mod=(int)((n-1)%26);
            sb.append((char)(mod+97));
            n=(n-1)/26;
        }
        sb.reverse();
        pw.println(sb.toString());
        pw.flush();
        pw.close();
    }
} Main public static void main(String ars[])throws Exception
    {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw=new PrintWriter(System.out);
        //String str[]=br.readLine().split(" ");
        long n=Long.parseLong(br.readLine());
        //int k=Integer.parseInt(str[1]);
        StringBuffer sb=new StringBuffer();
        while(n>0)
        {
            int mod=(int)((n-1)%26);
            sb.append((char)(mod+97));
            n=(n-1)/26;
        }
        sb.reverse();
        pw.println(sb.toString());
        pw.flush();
        pw.close();
    } main {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw=new PrintWriter(System.out);
        //String str[]=br.readLine().split(" ");
        long n=Long.parseLong(br.readLine());
        //int k=Integer.parseInt(str[1]);
        StringBuffer sb=new StringBuffer();
        while(n>0)
        {
            int mod=(int)((n-1)%26);
            sb.append((char)(mod+97));
            n=(n-1)/26;
        }
        sb.reverse();
        pw.println(sb.toString());
        pw.flush();
        pw.close();
    } BufferedReader br=new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) PrintWriter pw=new PrintWriter(System.out); pw new PrintWriter(System.out) long n=Long.parseLong(br.readLine()); n Long.parseLong(br.readLine()) Long.parseLong Long br.readLine() br.readLine br StringBuffer sb=new StringBuffer(); sb new StringBuffer() while(n>0)
        {
            int mod=(int)((n-1)%26);
            sb.append((char)(mod+97));
            n=(n-1)/26;
        } n>0 n 0 {
            int mod=(int)((n-1)%26);
            sb.append((char)(mod+97));
            n=(n-1)/26;
        } int mod=(int)((n-1)%26); mod (int)((n-1)%26) (n-1) n 1 26 sb.append((char)(mod+97)) sb.append sb (char)(mod+97) mod 97 n=(n-1)/26 n (n-1)/26 (n-1) n 1 26 sb.reverse() sb.reverse sb pw.println(sb.toString()) pw.println pw sb.toString() sb.toString sb pw.flush() pw.flush pw pw.close() pw.close pw String ars[] ars public class Main
{
    public static void main(String ars[])throws Exception
    {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw=new PrintWriter(System.out);
        //String str[]=br.readLine().split(" ");
        long n=Long.parseLong(br.readLine());
        //int k=Integer.parseInt(str[1]);
        StringBuffer sb=new StringBuffer();
        while(n>0)
        {
            int mod=(int)((n-1)%26);
            sb.append((char)(mod+97));
            n=(n-1)/26;
        }
        sb.reverse();
        pw.println(sb.toString());
        pw.flush();
        pw.close();
    }
} public class Main
{
    public static void main(String ars[])throws Exception
    {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw=new PrintWriter(System.out);
        //String str[]=br.readLine().split(" ");
        long n=Long.parseLong(br.readLine());
        //int k=Integer.parseInt(str[1]);
        StringBuffer sb=new StringBuffer();
        while(n>0)
        {
            int mod=(int)((n-1)%26);
            sb.append((char)(mod+97));
            n=(n-1)/26;
        }
        sb.reverse();
        pw.println(sb.toString());
        pw.flush();
        pw.close();
    }
} Main
import java.util.*;
import java.io.*;
public class Main
{
    public static void main(String ars[])throws Exception
    {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw=new PrintWriter(System.out);
        //String str[]=br.readLine().split(" ");
        long n=Long.parseLong(br.readLine());
        //int k=Integer.parseInt(str[1]);
        StringBuffer sb=new StringBuffer();
        while(n>0)
        {
            int mod=(int)((n-1)%26);
            sb.append((char)(mod+97));
            n=(n-1)/26;
        }
        sb.reverse();
        pw.println(sb.toString());
        pw.flush();
        pw.close();
    }
}