import java.util.*;

public class Main {
  public static void main(String args[]) {
    Scanner scanner = new Scanner(System.in);
    StringBuilder sb = new StringBuilder();
    long n;
    n = scanner.nextLong();
   //System.out.println(n);
    while(n > 26) {
      int rem = (int) (n % 26);
      //System.out.println(rem);
      if(rem == 0)
        sb.append('z');
      else
        sb.append((char)('a' + rem - 1));
      //System.out.println(n%26);
      n = n / 26;
      if(rem == 0)
        n--;
    }
    sb.append((char)('a' + n -1));
    System.out.println(sb.reverse().toString());
  }
} import java.util.*; util.* java public class Main {
  public static void main(String args[]) {
    Scanner scanner = new Scanner(System.in);
    StringBuilder sb = new StringBuilder();
    long n;
    n = scanner.nextLong();
   //System.out.println(n);
    while(n > 26) {
      int rem = (int) (n % 26);
      //System.out.println(rem);
      if(rem == 0)
        sb.append('z');
      else
        sb.append((char)('a' + rem - 1));
      //System.out.println(n%26);
      n = n / 26;
      if(rem == 0)
        n--;
    }
    sb.append((char)('a' + n -1));
    System.out.println(sb.reverse().toString());
  }
} Main public static void main(String args[]) {
    Scanner scanner = new Scanner(System.in);
    StringBuilder sb = new StringBuilder();
    long n;
    n = scanner.nextLong();
   //System.out.println(n);
    while(n > 26) {
      int rem = (int) (n % 26);
      //System.out.println(rem);
      if(rem == 0)
        sb.append('z');
      else
        sb.append((char)('a' + rem - 1));
      //System.out.println(n%26);
      n = n / 26;
      if(rem == 0)
        n--;
    }
    sb.append((char)('a' + n -1));
    System.out.println(sb.reverse().toString());
  } main {
    Scanner scanner = new Scanner(System.in);
    StringBuilder sb = new StringBuilder();
    long n;
    n = scanner.nextLong();
   //System.out.println(n);
    while(n > 26) {
      int rem = (int) (n % 26);
      //System.out.println(rem);
      if(rem == 0)
        sb.append('z');
      else
        sb.append((char)('a' + rem - 1));
      //System.out.println(n%26);
      n = n / 26;
      if(rem == 0)
        n--;
    }
    sb.append((char)('a' + n -1));
    System.out.println(sb.reverse().toString());
  } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) StringBuilder sb = new StringBuilder(); sb new StringBuilder() long n; n n = scanner.nextLong() n scanner.nextLong() scanner.nextLong scanner while(n > 26) {
      int rem = (int) (n % 26);
      //System.out.println(rem);
      if(rem == 0)
        sb.append('z');
      else
        sb.append((char)('a' + rem - 1));
      //System.out.println(n%26);
      n = n / 26;
      if(rem == 0)
        n--;
    } n > 26 n 26 {
      int rem = (int) (n % 26);
      //System.out.println(rem);
      if(rem == 0)
        sb.append('z');
      else
        sb.append((char)('a' + rem - 1));
      //System.out.println(n%26);
      n = n / 26;
      if(rem == 0)
        n--;
    } int rem = (int) (n % 26); rem (int) (n % 26) n 26 if(rem == 0)
        sb.append('z');
      else
        sb.append((char)('a' + rem - 1)); rem == 0 rem 0 sb.append('z') sb.append sb 'z' sb.append((char)('a' + rem - 1)) sb.append sb (char)('a' + rem - 1) 'a' + rem 'a' rem 1 n = n / 26 n n / 26 n 26 if(rem == 0)
        n--; rem == 0 rem 0 n-- n sb.append((char)('a' + n -1)) sb.append sb (char)('a' + n -1) 'a' + n 'a' n 1 System.out.println(sb.reverse().toString()) System.out.println System.out System System.out sb.reverse().toString() sb.reverse().toString sb.reverse() sb.reverse sb String args[] args public class Main {
  public static void main(String args[]) {
    Scanner scanner = new Scanner(System.in);
    StringBuilder sb = new StringBuilder();
    long n;
    n = scanner.nextLong();
   //System.out.println(n);
    while(n > 26) {
      int rem = (int) (n % 26);
      //System.out.println(rem);
      if(rem == 0)
        sb.append('z');
      else
        sb.append((char)('a' + rem - 1));
      //System.out.println(n%26);
      n = n / 26;
      if(rem == 0)
        n--;
    }
    sb.append((char)('a' + n -1));
    System.out.println(sb.reverse().toString());
  }
} public class Main {
  public static void main(String args[]) {
    Scanner scanner = new Scanner(System.in);
    StringBuilder sb = new StringBuilder();
    long n;
    n = scanner.nextLong();
   //System.out.println(n);
    while(n > 26) {
      int rem = (int) (n % 26);
      //System.out.println(rem);
      if(rem == 0)
        sb.append('z');
      else
        sb.append((char)('a' + rem - 1));
      //System.out.println(n%26);
      n = n / 26;
      if(rem == 0)
        n--;
    }
    sb.append((char)('a' + n -1));
    System.out.println(sb.reverse().toString());
  }
} Main
import java.util.*;

public class Main {
  public static void main(String args[]) {
    Scanner scanner = new Scanner(System.in);
    StringBuilder sb = new StringBuilder();
    long n;
    n = scanner.nextLong();
   //System.out.println(n);
    while(n > 26) {
      int rem = (int) (n % 26);
      //System.out.println(rem);
      if(rem == 0)
        sb.append('z');
      else
        sb.append((char)('a' + rem - 1));
      //System.out.println(n%26);
      n = n / 26;
      if(rem == 0)
        n--;
    }
    sb.append((char)('a' + n -1));
    System.out.println(sb.reverse().toString());
  }
}