import java.util.*;
public class Main {
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc=new Scanner(System.in);
		long n=sc.nextLong();
		String ans="";
		char c[]=new char[12];
		int q=0;
		
		while(n>0) {
			n--;
			c[q++]=(char)(n%26+'a');
			n/=26;
		}
		
		for(int i=q-1;i>=0;i--) {
			System.out.print(c[i]);
		}
		System.out.println();
	}
	
	

} import java.util.*; util.* java public class Main {
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc=new Scanner(System.in);
		long n=sc.nextLong();
		String ans="";
		char c[]=new char[12];
		int q=0;
		
		while(n>0) {
			n--;
			c[q++]=(char)(n%26+'a');
			n/=26;
		}
		
		for(int i=q-1;i>=0;i--) {
			System.out.print(c[i]);
		}
		System.out.println();
	}
	
	

} Main public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc=new Scanner(System.in);
		long n=sc.nextLong();
		String ans="";
		char c[]=new char[12];
		int q=0;
		
		while(n>0) {
			n--;
			c[q++]=(char)(n%26+'a');
			n/=26;
		}
		
		for(int i=q-1;i>=0;i--) {
			System.out.print(c[i]);
		}
		System.out.println();
	} main {
		// TODO Auto-generated method stub
		Scanner sc=new Scanner(System.in);
		long n=sc.nextLong();
		String ans="";
		char c[]=new char[12];
		int q=0;
		
		while(n>0) {
			n--;
			c[q++]=(char)(n%26+'a');
			n/=26;
		}
		
		for(int i=q-1;i>=0;i--) {
			System.out.print(c[i]);
		}
		System.out.println();
	} Scanner sc=new Scanner(System.in); sc new Scanner(System.in) long n=sc.nextLong(); n sc.nextLong() sc.nextLong sc String ans=""; ans "" char c[]=new char[12]; c new char[12] 12 int q=0; q 0 while(n>0) {
			n--;
			c[q++]=(char)(n%26+'a');
			n/=26;
		} n>0 n 0 {
			n--;
			c[q++]=(char)(n%26+'a');
			n/=26;
		} n-- n c[q++]=(char)(n%26+'a') c[q++] c q++ q (char)(n%26+'a') n%26 n 26 'a' n/=26 n 26 for(int i=q-1;i>=0;i--) {
			System.out.print(c[i]);
		} int i=q-1; int i=q-1; i q-1 q 1 i>=0 i 0 i-- i-- i {
			System.out.print(c[i]);
		} {
			System.out.print(c[i]);
		} System.out.print(c[i]) System.out.print System.out System System.out c[i] c i System.out.println() System.out.println System.out System System.out String[] args args public class Main {
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc=new Scanner(System.in);
		long n=sc.nextLong();
		String ans="";
		char c[]=new char[12];
		int q=0;
		
		while(n>0) {
			n--;
			c[q++]=(char)(n%26+'a');
			n/=26;
		}
		
		for(int i=q-1;i>=0;i--) {
			System.out.print(c[i]);
		}
		System.out.println();
	}
	
	

} public class Main {
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc=new Scanner(System.in);
		long n=sc.nextLong();
		String ans="";
		char c[]=new char[12];
		int q=0;
		
		while(n>0) {
			n--;
			c[q++]=(char)(n%26+'a');
			n/=26;
		}
		
		for(int i=q-1;i>=0;i--) {
			System.out.print(c[i]);
		}
		System.out.println();
	}
	
	

} Main
import java.util.*;
public class Main {
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc=new Scanner(System.in);
		long n=sc.nextLong();
		String ans="";
		char c[]=new char[12];
		int q=0;
		
		while(n>0) {
			n--;
			c[q++]=(char)(n%26+'a');
			n/=26;
		}
		
		for(int i=q-1;i>=0;i--) {
			System.out.print(c[i]);
		}
		System.out.println();
	}
	
	

}