import java.io.*;
import java.util.*;
public class Main{
	public static void main(String args[]) throws IOException{
               BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));	
		long N= Long.parseLong(reader.readLine());
		String res = "";
		while(N>0){
			N--;
			res =  (char)('a'+ N%26)+ res;
			N/=26;			
		}
		System.out.println(res);
	}
	private static String getCharForNumber(int i) {
    	char[] alphabet = "zabcdefghijklmnopqrstuvwxyz".toCharArray();
    	return Character.toString(alphabet[i]);
	}
} import java.io.*; io.* java import java.util.*; util.* java public class Main{
	public static void main(String args[]) throws IOException{
               BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));	
		long N= Long.parseLong(reader.readLine());
		String res = "";
		while(N>0){
			N--;
			res =  (char)('a'+ N%26)+ res;
			N/=26;			
		}
		System.out.println(res);
	}
	private static String getCharForNumber(int i) {
    	char[] alphabet = "zabcdefghijklmnopqrstuvwxyz".toCharArray();
    	return Character.toString(alphabet[i]);
	}
} Main public static void main(String args[]) throws IOException{
               BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));	
		long N= Long.parseLong(reader.readLine());
		String res = "";
		while(N>0){
			N--;
			res =  (char)('a'+ N%26)+ res;
			N/=26;			
		}
		System.out.println(res);
	} main {
               BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));	
		long N= Long.parseLong(reader.readLine());
		String res = "";
		while(N>0){
			N--;
			res =  (char)('a'+ N%26)+ res;
			N/=26;			
		}
		System.out.println(res);
	} BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); reader new BufferedReader(new InputStreamReader(System.in)) long N= Long.parseLong(reader.readLine()); N Long.parseLong(reader.readLine()) Long.parseLong Long reader.readLine() reader.readLine reader String res = ""; res "" while(N>0){
			N--;
			res =  (char)('a'+ N%26)+ res;
			N/=26;			
		} N>0 N 0 {
			N--;
			res =  (char)('a'+ N%26)+ res;
			N/=26;			
		} N-- N res =  (char)('a'+ N%26)+ res res (char)('a'+ N%26)+ res (char)('a'+ N%26) 'a' N%26 N 26 res N/=26 N 26 System.out.println(res) System.out.println System.out System System.out res String args[] args private static String getCharForNumber(int i) {
    	char[] alphabet = "zabcdefghijklmnopqrstuvwxyz".toCharArray();
    	return Character.toString(alphabet[i]);
	} getCharForNumber {
    	char[] alphabet = "zabcdefghijklmnopqrstuvwxyz".toCharArray();
    	return Character.toString(alphabet[i]);
	} char[] alphabet = "zabcdefghijklmnopqrstuvwxyz".toCharArray(); alphabet "zabcdefghijklmnopqrstuvwxyz".toCharArray() "zabcdefghijklmnopqrstuvwxyz".toCharArray "zabcdefghijklmnopqrstuvwxyz" return Character.toString(alphabet[i]); Character.toString(alphabet[i]) Character.toString Character alphabet[i] alphabet i int i i public class Main{
	public static void main(String args[]) throws IOException{
               BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));	
		long N= Long.parseLong(reader.readLine());
		String res = "";
		while(N>0){
			N--;
			res =  (char)('a'+ N%26)+ res;
			N/=26;			
		}
		System.out.println(res);
	}
	private static String getCharForNumber(int i) {
    	char[] alphabet = "zabcdefghijklmnopqrstuvwxyz".toCharArray();
    	return Character.toString(alphabet[i]);
	}
} public class Main{
	public static void main(String args[]) throws IOException{
               BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));	
		long N= Long.parseLong(reader.readLine());
		String res = "";
		while(N>0){
			N--;
			res =  (char)('a'+ N%26)+ res;
			N/=26;			
		}
		System.out.println(res);
	}
	private static String getCharForNumber(int i) {
    	char[] alphabet = "zabcdefghijklmnopqrstuvwxyz".toCharArray();
    	return Character.toString(alphabet[i]);
	}
} Main
import java.io.*;
import java.util.*;
public class Main{
	public static void main(String args[]) throws IOException{
               BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));	
		long N= Long.parseLong(reader.readLine());
		String res = "";
		while(N>0){
			N--;
			res =  (char)('a'+ N%26)+ res;
			N/=26;			
		}
		System.out.println(res);
	}
	private static String getCharForNumber(int i) {
    	char[] alphabet = "zabcdefghijklmnopqrstuvwxyz".toCharArray();
    	return Character.toString(alphabet[i]);
	}
}
