import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner sc= new Scanner(System.in);
        long N = sc.nextLong();
        StringBuilder ans = new StringBuilder();
       while(N > 0){
        long kari =  N % 26l;
          if(kari == 0) kari = 26;
          char alp = (char) (96 + kari);
          ans.append(alp);
         N -= 1;
         N /= 26l;
       }
      ans.reverse();
      System.out.println(ans.toString());
    } 
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner sc= new Scanner(System.in);
        long N = sc.nextLong();
        StringBuilder ans = new StringBuilder();
       while(N > 0){
        long kari =  N % 26l;
          if(kari == 0) kari = 26;
          char alp = (char) (96 + kari);
          ans.append(alp);
         N -= 1;
         N /= 26l;
       }
      ans.reverse();
      System.out.println(ans.toString());
    } 
} Main public static void main(String[] args) {
        Scanner sc= new Scanner(System.in);
        long N = sc.nextLong();
        StringBuilder ans = new StringBuilder();
       while(N > 0){
        long kari =  N % 26l;
          if(kari == 0) kari = 26;
          char alp = (char) (96 + kari);
          ans.append(alp);
         N -= 1;
         N /= 26l;
       }
      ans.reverse();
      System.out.println(ans.toString());
    } main {
        Scanner sc= new Scanner(System.in);
        long N = sc.nextLong();
        StringBuilder ans = new StringBuilder();
       while(N > 0){
        long kari =  N % 26l;
          if(kari == 0) kari = 26;
          char alp = (char) (96 + kari);
          ans.append(alp);
         N -= 1;
         N /= 26l;
       }
      ans.reverse();
      System.out.println(ans.toString());
    } Scanner sc= new Scanner(System.in); sc new Scanner(System.in) long N = sc.nextLong(); N sc.nextLong() sc.nextLong sc StringBuilder ans = new StringBuilder(); ans new StringBuilder() while(N > 0){
        long kari =  N % 26l;
          if(kari == 0) kari = 26;
          char alp = (char) (96 + kari);
          ans.append(alp);
         N -= 1;
         N /= 26l;
       } N > 0 N 0 {
        long kari =  N % 26l;
          if(kari == 0) kari = 26;
          char alp = (char) (96 + kari);
          ans.append(alp);
         N -= 1;
         N /= 26l;
       } long kari =  N % 26l; kari N % 26l N 26l if(kari == 0) kari = 26; kari == 0 kari 0 kari = 26 kari 26 char alp = (char) (96 + kari); alp (char) (96 + kari) 96 kari ans.append(alp) ans.append ans alp N -= 1 N 1 N /= 26l N 26l ans.reverse() ans.reverse ans System.out.println(ans.toString()) System.out.println System.out System System.out ans.toString() ans.toString ans String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc= new Scanner(System.in);
        long N = sc.nextLong();
        StringBuilder ans = new StringBuilder();
       while(N > 0){
        long kari =  N % 26l;
          if(kari == 0) kari = 26;
          char alp = (char) (96 + kari);
          ans.append(alp);
         N -= 1;
         N /= 26l;
       }
      ans.reverse();
      System.out.println(ans.toString());
    } 
} public class Main {
    public static void main(String[] args) {
        Scanner sc= new Scanner(System.in);
        long N = sc.nextLong();
        StringBuilder ans = new StringBuilder();
       while(N > 0){
        long kari =  N % 26l;
          if(kari == 0) kari = 26;
          char alp = (char) (96 + kari);
          ans.append(alp);
         N -= 1;
         N /= 26l;
       }
      ans.reverse();
      System.out.println(ans.toString());
    } 
} Main
import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner sc= new Scanner(System.in);
        long N = sc.nextLong();
        StringBuilder ans = new StringBuilder();
       while(N > 0){
        long kari =  N % 26l;
          if(kari == 0) kari = 26;
          char alp = (char) (96 + kari);
          ans.append(alp);
         N -= 1;
         N /= 26l;
       }
      ans.reverse();
      System.out.println(ans.toString());
    } 
}