import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
		//System.out.println(n);
		String ans = "";
		while(n>0){
			n--;
			ans += (char)('a' + (n%26));
			//if(n<26) break;
			n = n/26;
		}
		for(int i=ans.length()-1 ; i>=0; i--){
			System.out.print(ans.charAt(i));
		}
		
	}

} import java.io.*; io.* java import java.util.*; util.* java import java.text.*; text.* java import java.math.*; math.* java import java.util.regex.*; regex.* java.util public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
		//System.out.println(n);
		String ans = "";
		while(n>0){
			n--;
			ans += (char)('a' + (n%26));
			//if(n<26) break;
			n = n/26;
		}
		for(int i=ans.length()-1 ; i>=0; i--){
			System.out.print(ans.charAt(i));
		}
		
	}

} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
		//System.out.println(n);
		String ans = "";
		while(n>0){
			n--;
			ans += (char)('a' + (n%26));
			//if(n<26) break;
			n = n/26;
		}
		for(int i=ans.length()-1 ; i>=0; i--){
			System.out.print(ans.charAt(i));
		}
		
	} main {
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
		//System.out.println(n);
		String ans = "";
		while(n>0){
			n--;
			ans += (char)('a' + (n%26));
			//if(n<26) break;
			n = n/26;
		}
		for(int i=ans.length()-1 ; i>=0; i--){
			System.out.print(ans.charAt(i));
		}
		
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc String ans = ""; ans "" while(n>0){
			n--;
			ans += (char)('a' + (n%26));
			//if(n<26) break;
			n = n/26;
		} n>0 n 0 {
			n--;
			ans += (char)('a' + (n%26));
			//if(n<26) break;
			n = n/26;
		} n-- n ans += (char)('a' + (n%26)) ans (char)('a' + (n%26)) 'a' (n%26) n 26 n = n/26 n n/26 n 26 for(int i=ans.length()-1 ; i>=0; i--){
			System.out.print(ans.charAt(i));
		} int i=ans.length()-1 ; int i=ans.length()-1 ; i ans.length()-1 ans.length() ans.length ans 1 i>=0 i 0 i-- i-- i {
			System.out.print(ans.charAt(i));
		} {
			System.out.print(ans.charAt(i));
		} System.out.print(ans.charAt(i)) System.out.print System.out System System.out ans.charAt(i) ans.charAt ans i String[] args args public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
		//System.out.println(n);
		String ans = "";
		while(n>0){
			n--;
			ans += (char)('a' + (n%26));
			//if(n<26) break;
			n = n/26;
		}
		for(int i=ans.length()-1 ; i>=0; i--){
			System.out.print(ans.charAt(i));
		}
		
	}

} public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
		//System.out.println(n);
		String ans = "";
		while(n>0){
			n--;
			ans += (char)('a' + (n%26));
			//if(n<26) break;
			n = n/26;
		}
		for(int i=ans.length()-1 ; i>=0; i--){
			System.out.print(ans.charAt(i));
		}
		
	}

} Main
import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long n = sc.nextLong();
		//System.out.println(n);
		String ans = "";
		while(n>0){
			n--;
			ans += (char)('a' + (n%26));
			//if(n<26) break;
			n = n/26;
		}
		for(int i=ans.length()-1 ; i>=0; i--){
			System.out.print(ans.charAt(i));
		}
		
	}

}