import java.util.ArrayList;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.Scanner;

public class Main {
  public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);
    long N = sc.nextLong();

    String name = "";
    String alphabet = "";
    for(char c = 'a'; c <= 'z'; c++){
      alphabet = alphabet + c;
    }

    for(int i=0; i<100; i++){
      if(N <= 26){
        name = alphabet.charAt((int)(N + 25) % 26) + name;
        System.out.println(name);
        return;
      }else{
        int index = (int)((N + 25) % 26);
        name = alphabet.charAt(index) + name;
        N = N - index;
        N = N / 26;
      }
    }
    return;
  }
} import java.util.ArrayList; ArrayList java.util import java.util.Arrays; Arrays java.util import java.util.LinkedList; LinkedList java.util 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();

    String name = "";
    String alphabet = "";
    for(char c = 'a'; c <= 'z'; c++){
      alphabet = alphabet + c;
    }

    for(int i=0; i<100; i++){
      if(N <= 26){
        name = alphabet.charAt((int)(N + 25) % 26) + name;
        System.out.println(name);
        return;
      }else{
        int index = (int)((N + 25) % 26);
        name = alphabet.charAt(index) + name;
        N = N - index;
        N = N / 26;
      }
    }
    return;
  }
} Main public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);
    long N = sc.nextLong();

    String name = "";
    String alphabet = "";
    for(char c = 'a'; c <= 'z'; c++){
      alphabet = alphabet + c;
    }

    for(int i=0; i<100; i++){
      if(N <= 26){
        name = alphabet.charAt((int)(N + 25) % 26) + name;
        System.out.println(name);
        return;
      }else{
        int index = (int)((N + 25) % 26);
        name = alphabet.charAt(index) + name;
        N = N - index;
        N = N / 26;
      }
    }
    return;
  } main {

    Scanner sc = new Scanner(System.in);
    long N = sc.nextLong();

    String name = "";
    String alphabet = "";
    for(char c = 'a'; c <= 'z'; c++){
      alphabet = alphabet + c;
    }

    for(int i=0; i<100; i++){
      if(N <= 26){
        name = alphabet.charAt((int)(N + 25) % 26) + name;
        System.out.println(name);
        return;
      }else{
        int index = (int)((N + 25) % 26);
        name = alphabet.charAt(index) + name;
        N = N - index;
        N = N / 26;
      }
    }
    return;
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long N = sc.nextLong(); N sc.nextLong() sc.nextLong sc String name = ""; name "" String alphabet = ""; alphabet "" for(char c = 'a'; c <= 'z'; c++){
      alphabet = alphabet + c;
    } char c = 'a'; char c = 'a'; c 'a' c <= 'z' c 'z' c++ c++ c {
      alphabet = alphabet + c;
    } {
      alphabet = alphabet + c;
    } alphabet = alphabet + c alphabet alphabet + c alphabet c for(int i=0; i<100; i++){
      if(N <= 26){
        name = alphabet.charAt((int)(N + 25) % 26) + name;
        System.out.println(name);
        return;
      }else{
        int index = (int)((N + 25) % 26);
        name = alphabet.charAt(index) + name;
        N = N - index;
        N = N / 26;
      }
    } int i=0; int i=0; i 0 i<100 i 100 i++ i++ i {
      if(N <= 26){
        name = alphabet.charAt((int)(N + 25) % 26) + name;
        System.out.println(name);
        return;
      }else{
        int index = (int)((N + 25) % 26);
        name = alphabet.charAt(index) + name;
        N = N - index;
        N = N / 26;
      }
    } {
      if(N <= 26){
        name = alphabet.charAt((int)(N + 25) % 26) + name;
        System.out.println(name);
        return;
      }else{
        int index = (int)((N + 25) % 26);
        name = alphabet.charAt(index) + name;
        N = N - index;
        N = N / 26;
      }
    } if(N <= 26){
        name = alphabet.charAt((int)(N + 25) % 26) + name;
        System.out.println(name);
        return;
      }else{
        int index = (int)((N + 25) % 26);
        name = alphabet.charAt(index) + name;
        N = N - index;
        N = N / 26;
      } N <= 26 N 26 {
        name = alphabet.charAt((int)(N + 25) % 26) + name;
        System.out.println(name);
        return;
      } name = alphabet.charAt((int)(N + 25) % 26) + name name alphabet.charAt((int)(N + 25) % 26) + name alphabet.charAt((int)(N + 25) % 26) alphabet.charAt alphabet (int)(N + 25) % 26 (int)(N + 25) N 25 26 name System.out.println(name) System.out.println System.out System System.out name return; {
        int index = (int)((N + 25) % 26);
        name = alphabet.charAt(index) + name;
        N = N - index;
        N = N / 26;
      } int index = (int)((N + 25) % 26); index (int)((N + 25) % 26) (N + 25) N 25 26 name = alphabet.charAt(index) + name name alphabet.charAt(index) + name alphabet.charAt(index) alphabet.charAt alphabet index name N = N - index N N - index N index N = N / 26 N N / 26 N 26 return; String[] args args public class Main {
  public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);
    long N = sc.nextLong();

    String name = "";
    String alphabet = "";
    for(char c = 'a'; c <= 'z'; c++){
      alphabet = alphabet + c;
    }

    for(int i=0; i<100; i++){
      if(N <= 26){
        name = alphabet.charAt((int)(N + 25) % 26) + name;
        System.out.println(name);
        return;
      }else{
        int index = (int)((N + 25) % 26);
        name = alphabet.charAt(index) + name;
        N = N - index;
        N = N / 26;
      }
    }
    return;
  }
} public class Main {
  public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);
    long N = sc.nextLong();

    String name = "";
    String alphabet = "";
    for(char c = 'a'; c <= 'z'; c++){
      alphabet = alphabet + c;
    }

    for(int i=0; i<100; i++){
      if(N <= 26){
        name = alphabet.charAt((int)(N + 25) % 26) + name;
        System.out.println(name);
        return;
      }else{
        int index = (int)((N + 25) % 26);
        name = alphabet.charAt(index) + name;
        N = N - index;
        N = N / 26;
      }
    }
    return;
  }
} Main
import java.util.ArrayList;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.Scanner;

public class Main {
  public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);
    long N = sc.nextLong();

    String name = "";
    String alphabet = "";
    for(char c = 'a'; c <= 'z'; c++){
      alphabet = alphabet + c;
    }

    for(int i=0; i<100; i++){
      if(N <= 26){
        name = alphabet.charAt((int)(N + 25) % 26) + name;
        System.out.println(name);
        return;
      }else{
        int index = (int)((N + 25) % 26);
        name = alphabet.charAt(index) + name;
        N = N - index;
        N = N / 26;
      }
    }
    return;
  }
}