import java.util.*;

public class Main {
  public static void main(String[] args) throws Exception {
    Scanner sc = new Scanner(System.in);
    Long N = sc.nextLong();
    
    String name = "";
    
    while(N>0){
      N = N-1;
      String x = String.valueOf(Character.toChars((int)(N%26)+97));
      name = x.concat(name);
      if(N >=26){
        N = (Long)N/26;
      } else {
        break;
      }
    }
    System.out.println(name);
  }
} import java.util.*; util.* java public class Main {
  public static void main(String[] args) throws Exception {
    Scanner sc = new Scanner(System.in);
    Long N = sc.nextLong();
    
    String name = "";
    
    while(N>0){
      N = N-1;
      String x = String.valueOf(Character.toChars((int)(N%26)+97));
      name = x.concat(name);
      if(N >=26){
        N = (Long)N/26;
      } else {
        break;
      }
    }
    System.out.println(name);
  }
} Main public static void main(String[] args) throws Exception {
    Scanner sc = new Scanner(System.in);
    Long N = sc.nextLong();
    
    String name = "";
    
    while(N>0){
      N = N-1;
      String x = String.valueOf(Character.toChars((int)(N%26)+97));
      name = x.concat(name);
      if(N >=26){
        N = (Long)N/26;
      } else {
        break;
      }
    }
    System.out.println(name);
  } main {
    Scanner sc = new Scanner(System.in);
    Long N = sc.nextLong();
    
    String name = "";
    
    while(N>0){
      N = N-1;
      String x = String.valueOf(Character.toChars((int)(N%26)+97));
      name = x.concat(name);
      if(N >=26){
        N = (Long)N/26;
      } else {
        break;
      }
    }
    System.out.println(name);
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) Long N = sc.nextLong(); N sc.nextLong() sc.nextLong sc String name = ""; name "" while(N>0){
      N = N-1;
      String x = String.valueOf(Character.toChars((int)(N%26)+97));
      name = x.concat(name);
      if(N >=26){
        N = (Long)N/26;
      } else {
        break;
      }
    } N>0 N 0 {
      N = N-1;
      String x = String.valueOf(Character.toChars((int)(N%26)+97));
      name = x.concat(name);
      if(N >=26){
        N = (Long)N/26;
      } else {
        break;
      }
    } N = N-1 N N-1 N 1 String x = String.valueOf(Character.toChars((int)(N%26)+97)); x String.valueOf(Character.toChars((int)(N%26)+97)) String.valueOf String Character.toChars((int)(N%26)+97) Character.toChars Character (int)(N%26)+97 (int)(N%26) N 26 97 name = x.concat(name) name x.concat(name) x.concat x name if(N >=26){
        N = (Long)N/26;
      } else {
        break;
      } N >=26 N 26 {
        N = (Long)N/26;
      } N = (Long)N/26 N (Long)N/26 (Long)N 26 {
        break;
      } break; System.out.println(name) System.out.println System.out System System.out name String[] args args public class Main {
  public static void main(String[] args) throws Exception {
    Scanner sc = new Scanner(System.in);
    Long N = sc.nextLong();
    
    String name = "";
    
    while(N>0){
      N = N-1;
      String x = String.valueOf(Character.toChars((int)(N%26)+97));
      name = x.concat(name);
      if(N >=26){
        N = (Long)N/26;
      } else {
        break;
      }
    }
    System.out.println(name);
  }
} public class Main {
  public static void main(String[] args) throws Exception {
    Scanner sc = new Scanner(System.in);
    Long N = sc.nextLong();
    
    String name = "";
    
    while(N>0){
      N = N-1;
      String x = String.valueOf(Character.toChars((int)(N%26)+97));
      name = x.concat(name);
      if(N >=26){
        N = (Long)N/26;
      } else {
        break;
      }
    }
    System.out.println(name);
  }
} Main
import java.util.*;

public class Main {
  public static void main(String[] args) throws Exception {
    Scanner sc = new Scanner(System.in);
    Long N = sc.nextLong();
    
    String name = "";
    
    while(N>0){
      N = N-1;
      String x = String.valueOf(Character.toChars((int)(N%26)+97));
      name = x.concat(name);
      if(N >=26){
        N = (Long)N/26;
      } else {
        break;
      }
    }
    System.out.println(name);
  }
}