import java.util.*;
class Main{
  public static void main(String args[]){
    Scanner obj=new Scanner(System.in);
    long n=obj.nextLong();
    StringBuilder result = new StringBuilder();

        while(n>0){
            n--;
            result.insert(0, (char)('a' + n % 26));
            n /= 26;
        }

        System.out.println(result.toString());
  }
} import java.util.*; util.* java class Main{
  public static void main(String args[]){
    Scanner obj=new Scanner(System.in);
    long n=obj.nextLong();
    StringBuilder result = new StringBuilder();

        while(n>0){
            n--;
            result.insert(0, (char)('a' + n % 26));
            n /= 26;
        }

        System.out.println(result.toString());
  }
} Main public static void main(String args[]){
    Scanner obj=new Scanner(System.in);
    long n=obj.nextLong();
    StringBuilder result = new StringBuilder();

        while(n>0){
            n--;
            result.insert(0, (char)('a' + n % 26));
            n /= 26;
        }

        System.out.println(result.toString());
  } main {
    Scanner obj=new Scanner(System.in);
    long n=obj.nextLong();
    StringBuilder result = new StringBuilder();

        while(n>0){
            n--;
            result.insert(0, (char)('a' + n % 26));
            n /= 26;
        }

        System.out.println(result.toString());
  } Scanner obj=new Scanner(System.in); obj new Scanner(System.in) long n=obj.nextLong(); n obj.nextLong() obj.nextLong obj StringBuilder result = new StringBuilder(); result new StringBuilder() while(n>0){
            n--;
            result.insert(0, (char)('a' + n % 26));
            n /= 26;
        } n>0 n 0 {
            n--;
            result.insert(0, (char)('a' + n % 26));
            n /= 26;
        } n-- n result.insert(0, (char)('a' + n % 26)) result.insert result 0 (char)('a' + n % 26) 'a' n % 26 n 26 n /= 26 n 26 System.out.println(result.toString()) System.out.println System.out System System.out result.toString() result.toString result String args[] args
import java.util.*;
class Main{
  public static void main(String args[]){
    Scanner obj=new Scanner(System.in);
    long n=obj.nextLong();
    StringBuilder result = new StringBuilder();

        while(n>0){
            n--;
            result.insert(0, (char)('a' + n % 26));
            n /= 26;
        }

        System.out.println(result.toString());
  }
}