import java.util.*;
public class Main {
 
  public static void main(String[] args) { 
      Scanner sc = new Scanner(System.in);
      long n = sc.nextLong();
      StringBuilder sb = new StringBuilder();
      boolean flag = false;
      if(n == 1) 
          flag = true;
      while(--n >= 1) {
        long res = n % 26;
        sb.append((char)((res) % 26 + 'a'));
        n /= 26 ;
        if(n == 1) 
          flag = true;
      }
      if(flag)
      sb.append('a');
      System.out.println(sb.reverse().toString());
  }
} import java.util.*; util.* java public class Main {
 
  public static void main(String[] args) { 
      Scanner sc = new Scanner(System.in);
      long n = sc.nextLong();
      StringBuilder sb = new StringBuilder();
      boolean flag = false;
      if(n == 1) 
          flag = true;
      while(--n >= 1) {
        long res = n % 26;
        sb.append((char)((res) % 26 + 'a'));
        n /= 26 ;
        if(n == 1) 
          flag = true;
      }
      if(flag)
      sb.append('a');
      System.out.println(sb.reverse().toString());
  }
} Main public static void main(String[] args) { 
      Scanner sc = new Scanner(System.in);
      long n = sc.nextLong();
      StringBuilder sb = new StringBuilder();
      boolean flag = false;
      if(n == 1) 
          flag = true;
      while(--n >= 1) {
        long res = n % 26;
        sb.append((char)((res) % 26 + 'a'));
        n /= 26 ;
        if(n == 1) 
          flag = true;
      }
      if(flag)
      sb.append('a');
      System.out.println(sb.reverse().toString());
  } main { 
      Scanner sc = new Scanner(System.in);
      long n = sc.nextLong();
      StringBuilder sb = new StringBuilder();
      boolean flag = false;
      if(n == 1) 
          flag = true;
      while(--n >= 1) {
        long res = n % 26;
        sb.append((char)((res) % 26 + 'a'));
        n /= 26 ;
        if(n == 1) 
          flag = true;
      }
      if(flag)
      sb.append('a');
      System.out.println(sb.reverse().toString());
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc StringBuilder sb = new StringBuilder(); sb new StringBuilder() boolean flag = false; flag false if(n == 1) 
          flag = true; n == 1 n 1 flag = true flag true while(--n >= 1) {
        long res = n % 26;
        sb.append((char)((res) % 26 + 'a'));
        n /= 26 ;
        if(n == 1) 
          flag = true;
      } --n >= 1 --n n 1 {
        long res = n % 26;
        sb.append((char)((res) % 26 + 'a'));
        n /= 26 ;
        if(n == 1) 
          flag = true;
      } long res = n % 26; res n % 26 n 26 sb.append((char)((res) % 26 + 'a')) sb.append sb (char)((res) % 26 + 'a') (res) % 26 (res) 26 'a' n /= 26 n 26 if(n == 1) 
          flag = true; n == 1 n 1 flag = true flag true if(flag)
      sb.append('a'); flag sb.append('a') sb.append sb 'a' 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 sc = new Scanner(System.in);
      long n = sc.nextLong();
      StringBuilder sb = new StringBuilder();
      boolean flag = false;
      if(n == 1) 
          flag = true;
      while(--n >= 1) {
        long res = n % 26;
        sb.append((char)((res) % 26 + 'a'));
        n /= 26 ;
        if(n == 1) 
          flag = true;
      }
      if(flag)
      sb.append('a');
      System.out.println(sb.reverse().toString());
  }
} public class Main {
 
  public static void main(String[] args) { 
      Scanner sc = new Scanner(System.in);
      long n = sc.nextLong();
      StringBuilder sb = new StringBuilder();
      boolean flag = false;
      if(n == 1) 
          flag = true;
      while(--n >= 1) {
        long res = n % 26;
        sb.append((char)((res) % 26 + 'a'));
        n /= 26 ;
        if(n == 1) 
          flag = true;
      }
      if(flag)
      sb.append('a');
      System.out.println(sb.reverse().toString());
  }
} Main
import java.util.*;
public class Main {
 
  public static void main(String[] args) { 
      Scanner sc = new Scanner(System.in);
      long n = sc.nextLong();
      StringBuilder sb = new StringBuilder();
      boolean flag = false;
      if(n == 1) 
          flag = true;
      while(--n >= 1) {
        long res = n % 26;
        sb.append((char)((res) % 26 + 'a'));
        n /= 26 ;
        if(n == 1) 
          flag = true;
      }
      if(flag)
      sb.append('a');
      System.out.println(sb.reverse().toString());
  }
}