

import java.util.ArrayList;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner scan=new Scanner(System.in);
		long n=scan.nextLong();
		ArrayList<Character> al=new ArrayList<Character>();
		while(n>0) {
			long x=(n-1)%26;
			al.add((char) ('a'+x));
			n=(n-1)/26;
		}
		for(int i=al.size()-1;i>=0;i--) {
			System.out.print(al.get(i));
		}
	}

} import java.util.ArrayList; ArrayList java.util import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		Scanner scan=new Scanner(System.in);
		long n=scan.nextLong();
		ArrayList<Character> al=new ArrayList<Character>();
		while(n>0) {
			long x=(n-1)%26;
			al.add((char) ('a'+x));
			n=(n-1)/26;
		}
		for(int i=al.size()-1;i>=0;i--) {
			System.out.print(al.get(i));
		}
	}

} Main public static void main(String[] args) {
		Scanner scan=new Scanner(System.in);
		long n=scan.nextLong();
		ArrayList<Character> al=new ArrayList<Character>();
		while(n>0) {
			long x=(n-1)%26;
			al.add((char) ('a'+x));
			n=(n-1)/26;
		}
		for(int i=al.size()-1;i>=0;i--) {
			System.out.print(al.get(i));
		}
	} main {
		Scanner scan=new Scanner(System.in);
		long n=scan.nextLong();
		ArrayList<Character> al=new ArrayList<Character>();
		while(n>0) {
			long x=(n-1)%26;
			al.add((char) ('a'+x));
			n=(n-1)/26;
		}
		for(int i=al.size()-1;i>=0;i--) {
			System.out.print(al.get(i));
		}
	} Scanner scan=new Scanner(System.in); scan new Scanner(System.in) long n=scan.nextLong(); n scan.nextLong() scan.nextLong scan ArrayList<Character> al=new ArrayList<Character>(); al new ArrayList<Character>() while(n>0) {
			long x=(n-1)%26;
			al.add((char) ('a'+x));
			n=(n-1)/26;
		} n>0 n 0 {
			long x=(n-1)%26;
			al.add((char) ('a'+x));
			n=(n-1)/26;
		} long x=(n-1)%26; x (n-1)%26 (n-1) n 1 26 al.add((char) ('a'+x)) al.add al (char) ('a'+x) 'a' x n=(n-1)/26 n (n-1)/26 (n-1) n 1 26 for(int i=al.size()-1;i>=0;i--) {
			System.out.print(al.get(i));
		} int i=al.size()-1; int i=al.size()-1; i al.size()-1 al.size() al.size al 1 i>=0 i 0 i-- i-- i {
			System.out.print(al.get(i));
		} {
			System.out.print(al.get(i));
		} System.out.print(al.get(i)) System.out.print System.out System System.out al.get(i) al.get al i String[] args args public class Main {

	public static void main(String[] args) {
		Scanner scan=new Scanner(System.in);
		long n=scan.nextLong();
		ArrayList<Character> al=new ArrayList<Character>();
		while(n>0) {
			long x=(n-1)%26;
			al.add((char) ('a'+x));
			n=(n-1)/26;
		}
		for(int i=al.size()-1;i>=0;i--) {
			System.out.print(al.get(i));
		}
	}

} public class Main {

	public static void main(String[] args) {
		Scanner scan=new Scanner(System.in);
		long n=scan.nextLong();
		ArrayList<Character> al=new ArrayList<Character>();
		while(n>0) {
			long x=(n-1)%26;
			al.add((char) ('a'+x));
			n=(n-1)/26;
		}
		for(int i=al.size()-1;i>=0;i--) {
			System.out.print(al.get(i));
		}
	}

} Main


import java.util.ArrayList;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner scan=new Scanner(System.in);
		long n=scan.nextLong();
		ArrayList<Character> al=new ArrayList<Character>();
		while(n>0) {
			long x=(n-1)%26;
			al.add((char) ('a'+x));
			n=(n-1)/26;
		}
		for(int i=al.size()-1;i>=0;i--) {
			System.out.print(al.get(i));
		}
	}

}
