import java.util.*;
import java.lang.*;
import java.io.*;

class Main {
    
    private static BufferedReader br;
    
	public static void main (String[] args) throws java.lang.Exception {
		br=  new BufferedReader(new InputStreamReader(System.in));
		long num = Long.parseLong(br.readLine());
		
		StringBuilder str = new StringBuilder();
		
	    while(num > 0){
	        int rem = (int)(num%26L);
	        if(rem == 0){
	            str.append('z');
	            num = num/26 -1;
	        }else{
	            char x = (char)(rem - 1 + 'a');
	            str.append(x);
	            num /= 26;
	        }
	    }
	    
	    System.out.println(str.reverse());
	}
} import java.util.*; util.* java import java.lang.*; lang.* java import java.io.*; io.* java class Main {
    
    private static BufferedReader br;
    
	public static void main (String[] args) throws java.lang.Exception {
		br=  new BufferedReader(new InputStreamReader(System.in));
		long num = Long.parseLong(br.readLine());
		
		StringBuilder str = new StringBuilder();
		
	    while(num > 0){
	        int rem = (int)(num%26L);
	        if(rem == 0){
	            str.append('z');
	            num = num/26 -1;
	        }else{
	            char x = (char)(rem - 1 + 'a');
	            str.append(x);
	            num /= 26;
	        }
	    }
	    
	    System.out.println(str.reverse());
	}
} Main private static BufferedReader br; br public static void main (String[] args) throws java.lang.Exception {
		br=  new BufferedReader(new InputStreamReader(System.in));
		long num = Long.parseLong(br.readLine());
		
		StringBuilder str = new StringBuilder();
		
	    while(num > 0){
	        int rem = (int)(num%26L);
	        if(rem == 0){
	            str.append('z');
	            num = num/26 -1;
	        }else{
	            char x = (char)(rem - 1 + 'a');
	            str.append(x);
	            num /= 26;
	        }
	    }
	    
	    System.out.println(str.reverse());
	} main {
		br=  new BufferedReader(new InputStreamReader(System.in));
		long num = Long.parseLong(br.readLine());
		
		StringBuilder str = new StringBuilder();
		
	    while(num > 0){
	        int rem = (int)(num%26L);
	        if(rem == 0){
	            str.append('z');
	            num = num/26 -1;
	        }else{
	            char x = (char)(rem - 1 + 'a');
	            str.append(x);
	            num /= 26;
	        }
	    }
	    
	    System.out.println(str.reverse());
	} br=  new BufferedReader(new InputStreamReader(System.in)) br new BufferedReader(new InputStreamReader(System.in)) long num = Long.parseLong(br.readLine()); num Long.parseLong(br.readLine()) Long.parseLong Long br.readLine() br.readLine br StringBuilder str = new StringBuilder(); str new StringBuilder() while(num > 0){
	        int rem = (int)(num%26L);
	        if(rem == 0){
	            str.append('z');
	            num = num/26 -1;
	        }else{
	            char x = (char)(rem - 1 + 'a');
	            str.append(x);
	            num /= 26;
	        }
	    } num > 0 num 0 {
	        int rem = (int)(num%26L);
	        if(rem == 0){
	            str.append('z');
	            num = num/26 -1;
	        }else{
	            char x = (char)(rem - 1 + 'a');
	            str.append(x);
	            num /= 26;
	        }
	    } int rem = (int)(num%26L); rem (int)(num%26L) num 26L if(rem == 0){
	            str.append('z');
	            num = num/26 -1;
	        }else{
	            char x = (char)(rem - 1 + 'a');
	            str.append(x);
	            num /= 26;
	        } rem == 0 rem 0 {
	            str.append('z');
	            num = num/26 -1;
	        } str.append('z') str.append str 'z' num = num/26 -1 num num/26 -1 num/26 num 26 1 {
	            char x = (char)(rem - 1 + 'a');
	            str.append(x);
	            num /= 26;
	        } char x = (char)(rem - 1 + 'a'); x (char)(rem - 1 + 'a') rem - 1 rem 1 'a' str.append(x) str.append str x num /= 26 num 26 System.out.println(str.reverse()) System.out.println System.out System System.out str.reverse() str.reverse str String[] args args
import java.util.*;
import java.lang.*;
import java.io.*;

class Main {
    
    private static BufferedReader br;
    
	public static void main (String[] args) throws java.lang.Exception {
		br=  new BufferedReader(new InputStreamReader(System.in));
		long num = Long.parseLong(br.readLine());
		
		StringBuilder str = new StringBuilder();
		
	    while(num > 0){
	        int rem = (int)(num%26L);
	        if(rem == 0){
	            str.append('z');
	            num = num/26 -1;
	        }else{
	            char x = (char)(rem - 1 + 'a');
	            str.append(x);
	            num /= 26;
	        }
	    }
	    
	    System.out.println(str.reverse());
	}
}