import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		long n = sc.nextLong();
      	ArrayList<Character> name = new ArrayList<>();

      	for(;n>0;){
         n -= 1;
         name.add((char)(n%26+97));
         n /= 26;
        }
      	String dog = "";
      	for(int i=name.size()-1;i>=0;i--){
          dog += String.valueOf(name.get(i));
        }
		// 出力
		System.out.println(dog);
	}
} import java.util.*; util.* java public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		long n = sc.nextLong();
      	ArrayList<Character> name = new ArrayList<>();

      	for(;n>0;){
         n -= 1;
         name.add((char)(n%26+97));
         n /= 26;
        }
      	String dog = "";
      	for(int i=name.size()-1;i>=0;i--){
          dog += String.valueOf(name.get(i));
        }
		// 出力
		System.out.println(dog);
	}
} Main public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		long n = sc.nextLong();
      	ArrayList<Character> name = new ArrayList<>();

      	for(;n>0;){
         n -= 1;
         name.add((char)(n%26+97));
         n /= 26;
        }
      	String dog = "";
      	for(int i=name.size()-1;i>=0;i--){
          dog += String.valueOf(name.get(i));
        }
		// 出力
		System.out.println(dog);
	} main {
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		long n = sc.nextLong();
      	ArrayList<Character> name = new ArrayList<>();

      	for(;n>0;){
         n -= 1;
         name.add((char)(n%26+97));
         n /= 26;
        }
      	String dog = "";
      	for(int i=name.size()-1;i>=0;i--){
          dog += String.valueOf(name.get(i));
        }
		// 出力
		System.out.println(dog);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc ArrayList<Character> name = new ArrayList<>(); name new ArrayList<>() for(;n>0;){
         n -= 1;
         name.add((char)(n%26+97));
         n /= 26;
        } ; n>0 n 0 {
         n -= 1;
         name.add((char)(n%26+97));
         n /= 26;
        } {
         n -= 1;
         name.add((char)(n%26+97));
         n /= 26;
        } n -= 1 n 1 name.add((char)(n%26+97)) name.add name (char)(n%26+97) n%26 n 26 97 n /= 26 n 26 String dog = ""; dog "" for(int i=name.size()-1;i>=0;i--){
          dog += String.valueOf(name.get(i));
        } int i=name.size()-1; int i=name.size()-1; i name.size()-1 name.size() name.size name 1 i>=0 i 0 i-- i-- i {
          dog += String.valueOf(name.get(i));
        } {
          dog += String.valueOf(name.get(i));
        } dog += String.valueOf(name.get(i)) dog String.valueOf(name.get(i)) String.valueOf String name.get(i) name.get name i System.out.println(dog) System.out.println System.out System System.out dog String[] args args public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		long n = sc.nextLong();
      	ArrayList<Character> name = new ArrayList<>();

      	for(;n>0;){
         n -= 1;
         name.add((char)(n%26+97));
         n /= 26;
        }
      	String dog = "";
      	for(int i=name.size()-1;i>=0;i--){
          dog += String.valueOf(name.get(i));
        }
		// 出力
		System.out.println(dog);
	}
} public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		long n = sc.nextLong();
      	ArrayList<Character> name = new ArrayList<>();

      	for(;n>0;){
         n -= 1;
         name.add((char)(n%26+97));
         n /= 26;
        }
      	String dog = "";
      	for(int i=name.size()-1;i>=0;i--){
          dog += String.valueOf(name.get(i));
        }
		// 出力
		System.out.println(dog);
	}
} Main
import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		long n = sc.nextLong();
      	ArrayList<Character> name = new ArrayList<>();

      	for(;n>0;){
         n -= 1;
         name.add((char)(n%26+97));
         n /= 26;
        }
      	String dog = "";
      	for(int i=name.size()-1;i>=0;i--){
          dog += String.valueOf(name.get(i));
        }
		// 出力
		System.out.println(dog);
	}
}