import java.util.*;
import java.io.*;
public class Main{
        public static void main(String[] args){
                Scanner sc = new Scanner(System.in);
                PrintWriter ou = new PrintWriter(System.out);
                long n = Long.parseLong(sc.next());
                sc.close();
                String s = "";
                boolean ebishu = true;
                while(ebishu){
                        if(n <= 0) ebishu = false;
                        else{
                                int i =(int) (n % (long)26);
                                if(i == 0) i += 26;
                                char q = (char)(i + 96);
                                s = q + s;
                                n--;
                                n /= 26;
                        }
                }
                ou.print(s + "\n");
                ou.flush();
        }
} import java.util.*; util.* java import java.io.*; io.* java public class Main{
        public static void main(String[] args){
                Scanner sc = new Scanner(System.in);
                PrintWriter ou = new PrintWriter(System.out);
                long n = Long.parseLong(sc.next());
                sc.close();
                String s = "";
                boolean ebishu = true;
                while(ebishu){
                        if(n <= 0) ebishu = false;
                        else{
                                int i =(int) (n % (long)26);
                                if(i == 0) i += 26;
                                char q = (char)(i + 96);
                                s = q + s;
                                n--;
                                n /= 26;
                        }
                }
                ou.print(s + "\n");
                ou.flush();
        }
} Main public static void main(String[] args){
                Scanner sc = new Scanner(System.in);
                PrintWriter ou = new PrintWriter(System.out);
                long n = Long.parseLong(sc.next());
                sc.close();
                String s = "";
                boolean ebishu = true;
                while(ebishu){
                        if(n <= 0) ebishu = false;
                        else{
                                int i =(int) (n % (long)26);
                                if(i == 0) i += 26;
                                char q = (char)(i + 96);
                                s = q + s;
                                n--;
                                n /= 26;
                        }
                }
                ou.print(s + "\n");
                ou.flush();
        } main {
                Scanner sc = new Scanner(System.in);
                PrintWriter ou = new PrintWriter(System.out);
                long n = Long.parseLong(sc.next());
                sc.close();
                String s = "";
                boolean ebishu = true;
                while(ebishu){
                        if(n <= 0) ebishu = false;
                        else{
                                int i =(int) (n % (long)26);
                                if(i == 0) i += 26;
                                char q = (char)(i + 96);
                                s = q + s;
                                n--;
                                n /= 26;
                        }
                }
                ou.print(s + "\n");
                ou.flush();
        } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) PrintWriter ou = new PrintWriter(System.out); ou new PrintWriter(System.out) long n = Long.parseLong(sc.next()); n Long.parseLong(sc.next()) Long.parseLong Long sc.next() sc.next sc sc.close() sc.close sc String s = ""; s "" boolean ebishu = true; ebishu true while(ebishu){
                        if(n <= 0) ebishu = false;
                        else{
                                int i =(int) (n % (long)26);
                                if(i == 0) i += 26;
                                char q = (char)(i + 96);
                                s = q + s;
                                n--;
                                n /= 26;
                        }
                } ebishu {
                        if(n <= 0) ebishu = false;
                        else{
                                int i =(int) (n % (long)26);
                                if(i == 0) i += 26;
                                char q = (char)(i + 96);
                                s = q + s;
                                n--;
                                n /= 26;
                        }
                } if(n <= 0) ebishu = false;
                        else{
                                int i =(int) (n % (long)26);
                                if(i == 0) i += 26;
                                char q = (char)(i + 96);
                                s = q + s;
                                n--;
                                n /= 26;
                        } n <= 0 n 0 ebishu = false ebishu false {
                                int i =(int) (n % (long)26);
                                if(i == 0) i += 26;
                                char q = (char)(i + 96);
                                s = q + s;
                                n--;
                                n /= 26;
                        } int i =(int) (n % (long)26); i (int) (n % (long)26) n (long)26 if(i == 0) i += 26; i == 0 i 0 i += 26 i 26 char q = (char)(i + 96); q (char)(i + 96) i 96 s = q + s s q + s q s n-- n n /= 26 n 26 ou.print(s + "\n") ou.print ou s + "\n" s "\n" ou.flush() ou.flush ou String[] args args public class Main{
        public static void main(String[] args){
                Scanner sc = new Scanner(System.in);
                PrintWriter ou = new PrintWriter(System.out);
                long n = Long.parseLong(sc.next());
                sc.close();
                String s = "";
                boolean ebishu = true;
                while(ebishu){
                        if(n <= 0) ebishu = false;
                        else{
                                int i =(int) (n % (long)26);
                                if(i == 0) i += 26;
                                char q = (char)(i + 96);
                                s = q + s;
                                n--;
                                n /= 26;
                        }
                }
                ou.print(s + "\n");
                ou.flush();
        }
} public class Main{
        public static void main(String[] args){
                Scanner sc = new Scanner(System.in);
                PrintWriter ou = new PrintWriter(System.out);
                long n = Long.parseLong(sc.next());
                sc.close();
                String s = "";
                boolean ebishu = true;
                while(ebishu){
                        if(n <= 0) ebishu = false;
                        else{
                                int i =(int) (n % (long)26);
                                if(i == 0) i += 26;
                                char q = (char)(i + 96);
                                s = q + s;
                                n--;
                                n /= 26;
                        }
                }
                ou.print(s + "\n");
                ou.flush();
        }
} Main
import java.util.*;
import java.io.*;
public class Main{
        public static void main(String[] args){
                Scanner sc = new Scanner(System.in);
                PrintWriter ou = new PrintWriter(System.out);
                long n = Long.parseLong(sc.next());
                sc.close();
                String s = "";
                boolean ebishu = true;
                while(ebishu){
                        if(n <= 0) ebishu = false;
                        else{
                                int i =(int) (n % (long)26);
                                if(i == 0) i += 26;
                                char q = (char)(i + 96);
                                s = q + s;
                                n--;
                                n /= 26;
                        }
                }
                ou.print(s + "\n");
                ou.flush();
        }
}