import java.util.*;

public class Main {
	 
	  public static String getKey(Long index){
		String colCode = "";
		char key='a';
		Long loop = index / 26;
		if(loop>0){
			colCode += getKey(loop-1);
		}
		key = (char) (key+index%26);
		colCode += key;
		return colCode;
	}

		public static void main(String[] args) {
	        Scanner sc = new Scanner(System.in);
	        Long n = sc.nextLong();
	        System.out.println(getKey(n-1)); 
		}
} import java.util.*; util.* java public class Main {
	 
	  public static String getKey(Long index){
		String colCode = "";
		char key='a';
		Long loop = index / 26;
		if(loop>0){
			colCode += getKey(loop-1);
		}
		key = (char) (key+index%26);
		colCode += key;
		return colCode;
	}

		public static void main(String[] args) {
	        Scanner sc = new Scanner(System.in);
	        Long n = sc.nextLong();
	        System.out.println(getKey(n-1)); 
		}
} Main public static String getKey(Long index){
		String colCode = "";
		char key='a';
		Long loop = index / 26;
		if(loop>0){
			colCode += getKey(loop-1);
		}
		key = (char) (key+index%26);
		colCode += key;
		return colCode;
	} getKey {
		String colCode = "";
		char key='a';
		Long loop = index / 26;
		if(loop>0){
			colCode += getKey(loop-1);
		}
		key = (char) (key+index%26);
		colCode += key;
		return colCode;
	} String colCode = ""; colCode "" char key='a'; key 'a' Long loop = index / 26; loop index / 26 index 26 if(loop>0){
			colCode += getKey(loop-1);
		} loop>0 loop 0 {
			colCode += getKey(loop-1);
		} colCode += getKey(loop-1) colCode getKey(loop-1) getKey loop-1 loop 1 key = (char) (key+index%26) key (char) (key+index%26) key index%26 index 26 colCode += key colCode key return colCode; colCode Long index index public static void main(String[] args) {
	        Scanner sc = new Scanner(System.in);
	        Long n = sc.nextLong();
	        System.out.println(getKey(n-1)); 
		} main {
	        Scanner sc = new Scanner(System.in);
	        Long n = sc.nextLong();
	        System.out.println(getKey(n-1)); 
		} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) Long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc System.out.println(getKey(n-1)) System.out.println System.out System System.out getKey(n-1) getKey n-1 n 1 String[] args args public class Main {
	 
	  public static String getKey(Long index){
		String colCode = "";
		char key='a';
		Long loop = index / 26;
		if(loop>0){
			colCode += getKey(loop-1);
		}
		key = (char) (key+index%26);
		colCode += key;
		return colCode;
	}

		public static void main(String[] args) {
	        Scanner sc = new Scanner(System.in);
	        Long n = sc.nextLong();
	        System.out.println(getKey(n-1)); 
		}
} public class Main {
	 
	  public static String getKey(Long index){
		String colCode = "";
		char key='a';
		Long loop = index / 26;
		if(loop>0){
			colCode += getKey(loop-1);
		}
		key = (char) (key+index%26);
		colCode += key;
		return colCode;
	}

		public static void main(String[] args) {
	        Scanner sc = new Scanner(System.in);
	        Long n = sc.nextLong();
	        System.out.println(getKey(n-1)); 
		}
} Main
import java.util.*;

public class Main {
	 
	  public static String getKey(Long index){
		String colCode = "";
		char key='a';
		Long loop = index / 26;
		if(loop>0){
			colCode += getKey(loop-1);
		}
		key = (char) (key+index%26);
		colCode += key;
		return colCode;
	}

		public static void main(String[] args) {
	        Scanner sc = new Scanner(System.in);
	        Long n = sc.nextLong();
	        System.out.println(getKey(n-1)); 
		}
}