
import java.util.*;

class Main {
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long N = sc.nextLong() -1;
		List<Integer> list = new ArrayList<>();
		
		while(N > 25) {
			list.add((int)(N % 26));
			 N = N / 26 - 1;
		}
		list.add((int)N);
		char[] alphabet = "abcdefghijklmnopqrstuvwxyz".toCharArray(); 
		String ans = "";
		
		//System.out.println(list.size());
		//System.out.println(list.get(list.size()-1));
		
		for(int i = 0; i < list.size(); i++) {
			int index = list.get(list.size()-i-1);
			ans += alphabet[index];
		}
		
		System.out.println(ans);		
	}
}

 import java.util.*; util.* java class Main {
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long N = sc.nextLong() -1;
		List<Integer> list = new ArrayList<>();
		
		while(N > 25) {
			list.add((int)(N % 26));
			 N = N / 26 - 1;
		}
		list.add((int)N);
		char[] alphabet = "abcdefghijklmnopqrstuvwxyz".toCharArray(); 
		String ans = "";
		
		//System.out.println(list.size());
		//System.out.println(list.get(list.size()-1));
		
		for(int i = 0; i < list.size(); i++) {
			int index = list.get(list.size()-i-1);
			ans += alphabet[index];
		}
		
		System.out.println(ans);		
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long N = sc.nextLong() -1;
		List<Integer> list = new ArrayList<>();
		
		while(N > 25) {
			list.add((int)(N % 26));
			 N = N / 26 - 1;
		}
		list.add((int)N);
		char[] alphabet = "abcdefghijklmnopqrstuvwxyz".toCharArray(); 
		String ans = "";
		
		//System.out.println(list.size());
		//System.out.println(list.get(list.size()-1));
		
		for(int i = 0; i < list.size(); i++) {
			int index = list.get(list.size()-i-1);
			ans += alphabet[index];
		}
		
		System.out.println(ans);		
	} main {
		Scanner sc = new Scanner(System.in);
		long N = sc.nextLong() -1;
		List<Integer> list = new ArrayList<>();
		
		while(N > 25) {
			list.add((int)(N % 26));
			 N = N / 26 - 1;
		}
		list.add((int)N);
		char[] alphabet = "abcdefghijklmnopqrstuvwxyz".toCharArray(); 
		String ans = "";
		
		//System.out.println(list.size());
		//System.out.println(list.get(list.size()-1));
		
		for(int i = 0; i < list.size(); i++) {
			int index = list.get(list.size()-i-1);
			ans += alphabet[index];
		}
		
		System.out.println(ans);		
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long N = sc.nextLong() -1; N sc.nextLong() -1 sc.nextLong() sc.nextLong sc 1 List<Integer> list = new ArrayList<>(); list new ArrayList<>() while(N > 25) {
			list.add((int)(N % 26));
			 N = N / 26 - 1;
		} N > 25 N 25 {
			list.add((int)(N % 26));
			 N = N / 26 - 1;
		} list.add((int)(N % 26)) list.add list (int)(N % 26) N 26 N = N / 26 - 1 N N / 26 - 1 N / 26 N 26 1 list.add((int)N) list.add list (int)N char[] alphabet = "abcdefghijklmnopqrstuvwxyz".toCharArray(); alphabet "abcdefghijklmnopqrstuvwxyz".toCharArray() "abcdefghijklmnopqrstuvwxyz".toCharArray "abcdefghijklmnopqrstuvwxyz" String ans = ""; ans "" for(int i = 0; i < list.size(); i++) {
			int index = list.get(list.size()-i-1);
			ans += alphabet[index];
		} int i = 0; int i = 0; i 0 i < list.size() i list.size() list.size list i++ i++ i {
			int index = list.get(list.size()-i-1);
			ans += alphabet[index];
		} {
			int index = list.get(list.size()-i-1);
			ans += alphabet[index];
		} int index = list.get(list.size()-i-1); index list.get(list.size()-i-1) list.get list list.size()-i-1 list.size()-i-1 list.size() list.size list i 1 ans += alphabet[index] ans alphabet[index] alphabet index System.out.println(ans) System.out.println System.out System System.out ans String[] args args

import java.util.*;

class Main {
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long N = sc.nextLong() -1;
		List<Integer> list = new ArrayList<>();
		
		while(N > 25) {
			list.add((int)(N % 26));
			 N = N / 26 - 1;
		}
		list.add((int)N);
		char[] alphabet = "abcdefghijklmnopqrstuvwxyz".toCharArray(); 
		String ans = "";
		
		//System.out.println(list.size());
		//System.out.println(list.get(list.size()-1));
		
		for(int i = 0; i < list.size(); i++) {
			int index = list.get(list.size()-i-1);
			ans += alphabet[index];
		}
		
		System.out.println(ans);		
	}
}


