import java.util.*; 

class Main{
public static void main(String[] args){
	Scanner sc=new Scanner(System.in);
        long n=sc.nextLong();
        String ans="";
  		int c=0;
		String s="abcdefghijklmnopqrstuvwxyz";
  		String[] a=s.split("");
       
  
  		while(n>0){
         long b1=n/(long)Math.pow(26,c);
         long b2=b1%26;
            if(b2==0){
            b2=26;
            }
         ans=a[(int)b2-1]+ans;
         n=n-(long)Math.pow(26,c)*b2;
         c++;
           
        }
		

    	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();
        String ans="";
  		int c=0;
		String s="abcdefghijklmnopqrstuvwxyz";
  		String[] a=s.split("");
       
  
  		while(n>0){
         long b1=n/(long)Math.pow(26,c);
         long b2=b1%26;
            if(b2==0){
            b2=26;
            }
         ans=a[(int)b2-1]+ans;
         n=n-(long)Math.pow(26,c)*b2;
         c++;
           
        }
		

    	System.out.println(ans);
    }
} Main public static void main(String[] args){
	Scanner sc=new Scanner(System.in);
        long n=sc.nextLong();
        String ans="";
  		int c=0;
		String s="abcdefghijklmnopqrstuvwxyz";
  		String[] a=s.split("");
       
  
  		while(n>0){
         long b1=n/(long)Math.pow(26,c);
         long b2=b1%26;
            if(b2==0){
            b2=26;
            }
         ans=a[(int)b2-1]+ans;
         n=n-(long)Math.pow(26,c)*b2;
         c++;
           
        }
		

    	System.out.println(ans);
    } main {
	Scanner sc=new Scanner(System.in);
        long n=sc.nextLong();
        String ans="";
  		int c=0;
		String s="abcdefghijklmnopqrstuvwxyz";
  		String[] a=s.split("");
       
  
  		while(n>0){
         long b1=n/(long)Math.pow(26,c);
         long b2=b1%26;
            if(b2==0){
            b2=26;
            }
         ans=a[(int)b2-1]+ans;
         n=n-(long)Math.pow(26,c)*b2;
         c++;
           
        }
		

    	System.out.println(ans);
    } Scanner sc=new Scanner(System.in); sc new Scanner(System.in) long n=sc.nextLong(); n sc.nextLong() sc.nextLong sc String ans=""; ans "" int c=0; c 0 String s="abcdefghijklmnopqrstuvwxyz"; s "abcdefghijklmnopqrstuvwxyz" String[] a=s.split(""); a s.split("") s.split s "" while(n>0){
         long b1=n/(long)Math.pow(26,c);
         long b2=b1%26;
            if(b2==0){
            b2=26;
            }
         ans=a[(int)b2-1]+ans;
         n=n-(long)Math.pow(26,c)*b2;
         c++;
           
        } n>0 n 0 {
         long b1=n/(long)Math.pow(26,c);
         long b2=b1%26;
            if(b2==0){
            b2=26;
            }
         ans=a[(int)b2-1]+ans;
         n=n-(long)Math.pow(26,c)*b2;
         c++;
           
        } long b1=n/(long)Math.pow(26,c); b1 n/(long)Math.pow(26,c) n (long)Math.pow(26,c) Math.pow Math 26 c long b2=b1%26; b2 b1%26 b1 26 if(b2==0){
            b2=26;
            } b2==0 b2 0 {
            b2=26;
            } b2=26 b2 26 ans=a[(int)b2-1]+ans ans a[(int)b2-1]+ans a[(int)b2-1] a (int)b2-1 (int)b2 1 ans n=n-(long)Math.pow(26,c)*b2 n n-(long)Math.pow(26,c)*b2 n (long)Math.pow(26,c)*b2 (long)Math.pow(26,c) Math.pow Math 26 c b2 c++ c 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();
        String ans="";
  		int c=0;
		String s="abcdefghijklmnopqrstuvwxyz";
  		String[] a=s.split("");
       
  
  		while(n>0){
         long b1=n/(long)Math.pow(26,c);
         long b2=b1%26;
            if(b2==0){
            b2=26;
            }
         ans=a[(int)b2-1]+ans;
         n=n-(long)Math.pow(26,c)*b2;
         c++;
           
        }
		

    	System.out.println(ans);
    }
}