import java.util.*;
public class Main{
  public static void main(String[] args){
  	Scanner in = new Scanner(System.in);
        long n = in.nextLong();
        String s = "";
        while(n > 0) {
            long mod = n%26;
            if(mod != 0) {
                char c = (char) (96 + mod);
                s = c + s;
                n = n/26;
            } else {
                s = 'z' + s;
                n = n/26;
                n--;
            }
        }
        System.out.println(s);

    
  }
} import java.util.*; util.* java public class Main{
  public static void main(String[] args){
  	Scanner in = new Scanner(System.in);
        long n = in.nextLong();
        String s = "";
        while(n > 0) {
            long mod = n%26;
            if(mod != 0) {
                char c = (char) (96 + mod);
                s = c + s;
                n = n/26;
            } else {
                s = 'z' + s;
                n = n/26;
                n--;
            }
        }
        System.out.println(s);

    
  }
} Main public static void main(String[] args){
  	Scanner in = new Scanner(System.in);
        long n = in.nextLong();
        String s = "";
        while(n > 0) {
            long mod = n%26;
            if(mod != 0) {
                char c = (char) (96 + mod);
                s = c + s;
                n = n/26;
            } else {
                s = 'z' + s;
                n = n/26;
                n--;
            }
        }
        System.out.println(s);

    
  } main {
  	Scanner in = new Scanner(System.in);
        long n = in.nextLong();
        String s = "";
        while(n > 0) {
            long mod = n%26;
            if(mod != 0) {
                char c = (char) (96 + mod);
                s = c + s;
                n = n/26;
            } else {
                s = 'z' + s;
                n = n/26;
                n--;
            }
        }
        System.out.println(s);

    
  } Scanner in = new Scanner(System.in); in new Scanner(System.in) long n = in.nextLong(); n in.nextLong() in.nextLong in String s = ""; s "" while(n > 0) {
            long mod = n%26;
            if(mod != 0) {
                char c = (char) (96 + mod);
                s = c + s;
                n = n/26;
            } else {
                s = 'z' + s;
                n = n/26;
                n--;
            }
        } n > 0 n 0 {
            long mod = n%26;
            if(mod != 0) {
                char c = (char) (96 + mod);
                s = c + s;
                n = n/26;
            } else {
                s = 'z' + s;
                n = n/26;
                n--;
            }
        } long mod = n%26; mod n%26 n 26 if(mod != 0) {
                char c = (char) (96 + mod);
                s = c + s;
                n = n/26;
            } else {
                s = 'z' + s;
                n = n/26;
                n--;
            } mod != 0 mod 0 {
                char c = (char) (96 + mod);
                s = c + s;
                n = n/26;
            } char c = (char) (96 + mod); c (char) (96 + mod) 96 mod s = c + s s c + s c s n = n/26 n n/26 n 26 {
                s = 'z' + s;
                n = n/26;
                n--;
            } s = 'z' + s s 'z' + s 'z' s n = n/26 n n/26 n 26 n-- n System.out.println(s) System.out.println System.out System System.out s String[] args args public class Main{
  public static void main(String[] args){
  	Scanner in = new Scanner(System.in);
        long n = in.nextLong();
        String s = "";
        while(n > 0) {
            long mod = n%26;
            if(mod != 0) {
                char c = (char) (96 + mod);
                s = c + s;
                n = n/26;
            } else {
                s = 'z' + s;
                n = n/26;
                n--;
            }
        }
        System.out.println(s);

    
  }
} public class Main{
  public static void main(String[] args){
  	Scanner in = new Scanner(System.in);
        long n = in.nextLong();
        String s = "";
        while(n > 0) {
            long mod = n%26;
            if(mod != 0) {
                char c = (char) (96 + mod);
                s = c + s;
                n = n/26;
            } else {
                s = 'z' + s;
                n = n/26;
                n--;
            }
        }
        System.out.println(s);

    
  }
} Main
import java.util.*;
public class Main{
  public static void main(String[] args){
  	Scanner in = new Scanner(System.in);
        long n = in.nextLong();
        String s = "";
        while(n > 0) {
            long mod = n%26;
            if(mod != 0) {
                char c = (char) (96 + mod);
                s = c + s;
                n = n/26;
            } else {
                s = 'z' + s;
                n = n/26;
                n--;
            }
        }
        System.out.println(s);

    
  }
}
