import java.util.*;

public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        long n = scanner.nextLong();
        
        List<Character> list = new ArrayList<Character>();
        int i = 0;
        
        while (n != 0) {
            list.add((char) ((n - 1) % 26 + 'a'));
            n = (n - 1) / 26;
        }
        
        Collections.reverse(list);
        
        for(char c : list){
            System.out.print(c);
        }
    }
} import java.util.*; util.* java public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        long n = scanner.nextLong();
        
        List<Character> list = new ArrayList<Character>();
        int i = 0;
        
        while (n != 0) {
            list.add((char) ((n - 1) % 26 + 'a'));
            n = (n - 1) / 26;
        }
        
        Collections.reverse(list);
        
        for(char c : list){
            System.out.print(c);
        }
    }
} Main public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        long n = scanner.nextLong();
        
        List<Character> list = new ArrayList<Character>();
        int i = 0;
        
        while (n != 0) {
            list.add((char) ((n - 1) % 26 + 'a'));
            n = (n - 1) / 26;
        }
        
        Collections.reverse(list);
        
        for(char c : list){
            System.out.print(c);
        }
    } main {
        Scanner scanner = new Scanner(System.in);
        long n = scanner.nextLong();
        
        List<Character> list = new ArrayList<Character>();
        int i = 0;
        
        while (n != 0) {
            list.add((char) ((n - 1) % 26 + 'a'));
            n = (n - 1) / 26;
        }
        
        Collections.reverse(list);
        
        for(char c : list){
            System.out.print(c);
        }
    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) long n = scanner.nextLong(); n scanner.nextLong() scanner.nextLong scanner List<Character> list = new ArrayList<Character>(); list new ArrayList<Character>() int i = 0; i 0 while (n != 0) {
            list.add((char) ((n - 1) % 26 + 'a'));
            n = (n - 1) / 26;
        } n != 0 n 0 {
            list.add((char) ((n - 1) % 26 + 'a'));
            n = (n - 1) / 26;
        } list.add((char) ((n - 1) % 26 + 'a')) list.add list (char) ((n - 1) % 26 + 'a') (n - 1) % 26 (n - 1) n 1 26 'a' n = (n - 1) / 26 n (n - 1) / 26 (n - 1) n 1 26 Collections.reverse(list) Collections.reverse Collections list for(char c : list){
            System.out.print(c);
        } char c list {
            System.out.print(c);
        } {
            System.out.print(c);
        } System.out.print(c) System.out.print System.out System System.out c String[] args args public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        long n = scanner.nextLong();
        
        List<Character> list = new ArrayList<Character>();
        int i = 0;
        
        while (n != 0) {
            list.add((char) ((n - 1) % 26 + 'a'));
            n = (n - 1) / 26;
        }
        
        Collections.reverse(list);
        
        for(char c : list){
            System.out.print(c);
        }
    }
} public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        long n = scanner.nextLong();
        
        List<Character> list = new ArrayList<Character>();
        int i = 0;
        
        while (n != 0) {
            list.add((char) ((n - 1) % 26 + 'a'));
            n = (n - 1) / 26;
        }
        
        Collections.reverse(list);
        
        for(char c : list){
            System.out.print(c);
        }
    }
} Main
import java.util.*;

public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        long n = scanner.nextLong();
        
        List<Character> list = new ArrayList<Character>();
        int i = 0;
        
        while (n != 0) {
            list.add((char) ((n - 1) % 26 + 'a'));
            n = (n - 1) / 26;
        }
        
        Collections.reverse(list);
        
        for(char c : list){
            System.out.print(c);
        }
    }
}