public class Main {
  
  static char[] arr = ("abcdefghijklmnopqrstuvwxyz").toCharArray(); 
  
  public static void main(String[] args){
    long N = new java.util.Scanner(System.in).nextLong();

    System.out.println(getName(N, ""));
  }
  
  private static String getName(long n, String str) {
    long syo = n / 26L;
    int yo = (int)(n % 26L);
    
    if (yo == 0) {
      yo = 26;
      syo -= 1;
    }

    str = String.valueOf(arr[yo - 1]) + str;
    
    if (syo == 0) {
      return str;
    }
    return getName(syo, str);
  }
} public class Main {
  
  static char[] arr = ("abcdefghijklmnopqrstuvwxyz").toCharArray(); 
  
  public static void main(String[] args){
    long N = new java.util.Scanner(System.in).nextLong();

    System.out.println(getName(N, ""));
  }
  
  private static String getName(long n, String str) {
    long syo = n / 26L;
    int yo = (int)(n % 26L);
    
    if (yo == 0) {
      yo = 26;
      syo -= 1;
    }

    str = String.valueOf(arr[yo - 1]) + str;
    
    if (syo == 0) {
      return str;
    }
    return getName(syo, str);
  }
} Main static char[] arr = ("abcdefghijklmnopqrstuvwxyz").toCharArray(); arr ("abcdefghijklmnopqrstuvwxyz").toCharArray() ("abcdefghijklmnopqrstuvwxyz").toCharArray ("abcdefghijklmnopqrstuvwxyz") public static void main(String[] args){
    long N = new java.util.Scanner(System.in).nextLong();

    System.out.println(getName(N, ""));
  } main {
    long N = new java.util.Scanner(System.in).nextLong();

    System.out.println(getName(N, ""));
  } long N = new java.util.Scanner(System.in).nextLong(); N new java.util.Scanner(System.in).nextLong() new java.util.Scanner(System.in).nextLong new java.util.Scanner(System.in) System.out.println(getName(N, "")) System.out.println System.out System System.out getName(N, "") getName N "" String[] args args private static String getName(long n, String str) {
    long syo = n / 26L;
    int yo = (int)(n % 26L);
    
    if (yo == 0) {
      yo = 26;
      syo -= 1;
    }

    str = String.valueOf(arr[yo - 1]) + str;
    
    if (syo == 0) {
      return str;
    }
    return getName(syo, str);
  } getName {
    long syo = n / 26L;
    int yo = (int)(n % 26L);
    
    if (yo == 0) {
      yo = 26;
      syo -= 1;
    }

    str = String.valueOf(arr[yo - 1]) + str;
    
    if (syo == 0) {
      return str;
    }
    return getName(syo, str);
  } long syo = n / 26L; syo n / 26L n 26L int yo = (int)(n % 26L); yo (int)(n % 26L) n 26L if (yo == 0) {
      yo = 26;
      syo -= 1;
    } yo == 0 yo 0 {
      yo = 26;
      syo -= 1;
    } yo = 26 yo 26 syo -= 1 syo 1 str = String.valueOf(arr[yo - 1]) + str str String.valueOf(arr[yo - 1]) + str String.valueOf(arr[yo - 1]) String.valueOf String arr[yo - 1] arr yo - 1 yo 1 str if (syo == 0) {
      return str;
    } syo == 0 syo 0 {
      return str;
    } return str; str return getName(syo, str); getName(syo, str) getName syo str long n n String str str public class Main {
  
  static char[] arr = ("abcdefghijklmnopqrstuvwxyz").toCharArray(); 
  
  public static void main(String[] args){
    long N = new java.util.Scanner(System.in).nextLong();

    System.out.println(getName(N, ""));
  }
  
  private static String getName(long n, String str) {
    long syo = n / 26L;
    int yo = (int)(n % 26L);
    
    if (yo == 0) {
      yo = 26;
      syo -= 1;
    }

    str = String.valueOf(arr[yo - 1]) + str;
    
    if (syo == 0) {
      return str;
    }
    return getName(syo, str);
  }
} public class Main {
  
  static char[] arr = ("abcdefghijklmnopqrstuvwxyz").toCharArray(); 
  
  public static void main(String[] args){
    long N = new java.util.Scanner(System.in).nextLong();

    System.out.println(getName(N, ""));
  }
  
  private static String getName(long n, String str) {
    long syo = n / 26L;
    int yo = (int)(n % 26L);
    
    if (yo == 0) {
      yo = 26;
      syo -= 1;
    }

    str = String.valueOf(arr[yo - 1]) + str;
    
    if (syo == 0) {
      return str;
    }
    return getName(syo, str);
  }
} Main
public class Main {
  
  static char[] arr = ("abcdefghijklmnopqrstuvwxyz").toCharArray(); 
  
  public static void main(String[] args){
    long N = new java.util.Scanner(System.in).nextLong();

    System.out.println(getName(N, ""));
  }
  
  private static String getName(long n, String str) {
    long syo = n / 26L;
    int yo = (int)(n % 26L);
    
    if (yo == 0) {
      yo = 26;
      syo -= 1;
    }

    str = String.valueOf(arr[yo - 1]) + str;
    
    if (syo == 0) {
      return str;
    }
    return getName(syo, str);
  }
}
