import java.util.*;


public class Main {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);

    long N = Long.parseLong(scanner.nextLine());

    String name = "";

   name = calc(N, name);

   System.out.println(name);
    scanner.close();
    return;
  }

  public static String calc(long N, String name){
    char c = (char) (N % 26 + 'a' - 1);
    if( N%26 == 0){
      c = 'z';
      N -= 26;
    }
    name = String.valueOf(c) + name;
    N = N - N%26;
    if(N / 26 > 0){
      name = calc(N / 26, name);
    }
    return name;
  }
} import java.util.*; util.* java public class Main {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);

    long N = Long.parseLong(scanner.nextLine());

    String name = "";

   name = calc(N, name);

   System.out.println(name);
    scanner.close();
    return;
  }

  public static String calc(long N, String name){
    char c = (char) (N % 26 + 'a' - 1);
    if( N%26 == 0){
      c = 'z';
      N -= 26;
    }
    name = String.valueOf(c) + name;
    N = N - N%26;
    if(N / 26 > 0){
      name = calc(N / 26, name);
    }
    return name;
  }
} Main public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);

    long N = Long.parseLong(scanner.nextLine());

    String name = "";

   name = calc(N, name);

   System.out.println(name);
    scanner.close();
    return;
  } main {
    Scanner scanner = new Scanner(System.in);

    long N = Long.parseLong(scanner.nextLine());

    String name = "";

   name = calc(N, name);

   System.out.println(name);
    scanner.close();
    return;
  } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) long N = Long.parseLong(scanner.nextLine()); N Long.parseLong(scanner.nextLine()) Long.parseLong Long scanner.nextLine() scanner.nextLine scanner String name = ""; name "" name = calc(N, name) name calc(N, name) calc N name System.out.println(name) System.out.println System.out System System.out name scanner.close() scanner.close scanner return; String[] args args public static String calc(long N, String name){
    char c = (char) (N % 26 + 'a' - 1);
    if( N%26 == 0){
      c = 'z';
      N -= 26;
    }
    name = String.valueOf(c) + name;
    N = N - N%26;
    if(N / 26 > 0){
      name = calc(N / 26, name);
    }
    return name;
  } calc {
    char c = (char) (N % 26 + 'a' - 1);
    if( N%26 == 0){
      c = 'z';
      N -= 26;
    }
    name = String.valueOf(c) + name;
    N = N - N%26;
    if(N / 26 > 0){
      name = calc(N / 26, name);
    }
    return name;
  } char c = (char) (N % 26 + 'a' - 1); c (char) (N % 26 + 'a' - 1) N % 26 + 'a' N % 26 N 26 'a' 1 if( N%26 == 0){
      c = 'z';
      N -= 26;
    } N%26 == 0 N%26 N 26 0 {
      c = 'z';
      N -= 26;
    } c = 'z' c 'z' N -= 26 N 26 name = String.valueOf(c) + name name String.valueOf(c) + name String.valueOf(c) String.valueOf String c name N = N - N%26 N N - N%26 N N%26 N 26 if(N / 26 > 0){
      name = calc(N / 26, name);
    } N / 26 > 0 N / 26 N 26 0 {
      name = calc(N / 26, name);
    } name = calc(N / 26, name) name calc(N / 26, name) calc N / 26 N 26 name return name; name long N N String name name public class Main {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);

    long N = Long.parseLong(scanner.nextLine());

    String name = "";

   name = calc(N, name);

   System.out.println(name);
    scanner.close();
    return;
  }

  public static String calc(long N, String name){
    char c = (char) (N % 26 + 'a' - 1);
    if( N%26 == 0){
      c = 'z';
      N -= 26;
    }
    name = String.valueOf(c) + name;
    N = N - N%26;
    if(N / 26 > 0){
      name = calc(N / 26, name);
    }
    return name;
  }
} public class Main {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);

    long N = Long.parseLong(scanner.nextLine());

    String name = "";

   name = calc(N, name);

   System.out.println(name);
    scanner.close();
    return;
  }

  public static String calc(long N, String name){
    char c = (char) (N % 26 + 'a' - 1);
    if( N%26 == 0){
      c = 'z';
      N -= 26;
    }
    name = String.valueOf(c) + name;
    N = N - N%26;
    if(N / 26 > 0){
      name = calc(N / 26, name);
    }
    return name;
  }
} Main
import java.util.*;


public class Main {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);

    long N = Long.parseLong(scanner.nextLine());

    String name = "";

   name = calc(N, name);

   System.out.println(name);
    scanner.close();
    return;
  }

  public static String calc(long N, String name){
    char c = (char) (N % 26 + 'a' - 1);
    if( N%26 == 0){
      c = 'z';
      N -= 26;
    }
    name = String.valueOf(c) + name;
    N = N - N%26;
    if(N / 26 > 0){
      name = calc(N / 26, name);
    }
    return name;
  }
}
