import java.util.Scanner;

public class Main {

  public static void main(String[] args) {

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

    String[] list = new String[26];
    char tmp = 'a';
    for (int i = 0; i < 26; i++) {
      list[i] = String.valueOf(tmp++);
    }

    String ans = "";
    while (n > 0) {
      n--;
      int mod = (int) (n % 26);
      ans += list[mod];
      n /= 26;
    }

    StringBuffer str = new StringBuffer(ans);
    String s = str.reverse().toString();
    System.out.println(s);
  }
} 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[] list = new String[26];
    char tmp = 'a';
    for (int i = 0; i < 26; i++) {
      list[i] = String.valueOf(tmp++);
    }

    String ans = "";
    while (n > 0) {
      n--;
      int mod = (int) (n % 26);
      ans += list[mod];
      n /= 26;
    }

    StringBuffer str = new StringBuffer(ans);
    String s = str.reverse().toString();
    System.out.println(s);
  }
} Main public static void main(String[] args) {

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

    String[] list = new String[26];
    char tmp = 'a';
    for (int i = 0; i < 26; i++) {
      list[i] = String.valueOf(tmp++);
    }

    String ans = "";
    while (n > 0) {
      n--;
      int mod = (int) (n % 26);
      ans += list[mod];
      n /= 26;
    }

    StringBuffer str = new StringBuffer(ans);
    String s = str.reverse().toString();
    System.out.println(s);
  } main {

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

    String[] list = new String[26];
    char tmp = 'a';
    for (int i = 0; i < 26; i++) {
      list[i] = String.valueOf(tmp++);
    }

    String ans = "";
    while (n > 0) {
      n--;
      int mod = (int) (n % 26);
      ans += list[mod];
      n /= 26;
    }

    StringBuffer str = new StringBuffer(ans);
    String s = str.reverse().toString();
    System.out.println(s);
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc String[] list = new String[26]; list new String[26] 26 char tmp = 'a'; tmp 'a' for (int i = 0; i < 26; i++) {
      list[i] = String.valueOf(tmp++);
    } int i = 0; int i = 0; i 0 i < 26 i 26 i++ i++ i {
      list[i] = String.valueOf(tmp++);
    } {
      list[i] = String.valueOf(tmp++);
    } list[i] = String.valueOf(tmp++) list[i] list i String.valueOf(tmp++) String.valueOf String tmp++ tmp String ans = ""; ans "" while (n > 0) {
      n--;
      int mod = (int) (n % 26);
      ans += list[mod];
      n /= 26;
    } n > 0 n 0 {
      n--;
      int mod = (int) (n % 26);
      ans += list[mod];
      n /= 26;
    } n-- n int mod = (int) (n % 26); mod (int) (n % 26) n 26 ans += list[mod] ans list[mod] list mod n /= 26 n 26 StringBuffer str = new StringBuffer(ans); str new StringBuffer(ans) String s = str.reverse().toString(); s str.reverse().toString() str.reverse().toString str.reverse() str.reverse str System.out.println(s) System.out.println System.out System System.out s String[] args args public class Main {

  public static void main(String[] args) {

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

    String[] list = new String[26];
    char tmp = 'a';
    for (int i = 0; i < 26; i++) {
      list[i] = String.valueOf(tmp++);
    }

    String ans = "";
    while (n > 0) {
      n--;
      int mod = (int) (n % 26);
      ans += list[mod];
      n /= 26;
    }

    StringBuffer str = new StringBuffer(ans);
    String s = str.reverse().toString();
    System.out.println(s);
  }
} public class Main {

  public static void main(String[] args) {

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

    String[] list = new String[26];
    char tmp = 'a';
    for (int i = 0; i < 26; i++) {
      list[i] = String.valueOf(tmp++);
    }

    String ans = "";
    while (n > 0) {
      n--;
      int mod = (int) (n % 26);
      ans += list[mod];
      n /= 26;
    }

    StringBuffer str = new StringBuffer(ans);
    String s = str.reverse().toString();
    System.out.println(s);
  }
} Main
import java.util.Scanner;

public class Main {

  public static void main(String[] args) {

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

    String[] list = new String[26];
    char tmp = 'a';
    for (int i = 0; i < 26; i++) {
      list[i] = String.valueOf(tmp++);
    }

    String ans = "";
    while (n > 0) {
      n--;
      int mod = (int) (n % 26);
      ans += list[mod];
      n /= 26;
    }

    StringBuffer str = new StringBuffer(ans);
    String s = str.reverse().toString();
    System.out.println(s);
  }
}