Problem:
Score : 300 points

Problem Statement

1000000000000001 dogs suddenly appeared under the roof of Roger's house, all of which he decided to keep. The dogs had been numbered 1 through 1000000000000001, but he gave them new names, as follows:

the dogs numbered 1,2,\cdots,26 were respectively given the names a, b, ..., z;

the dogs numbered 27,28,29,\cdots,701,702 were respectively given the names aa, ab, ac, ..., zy, zz;

the dogs numbered 703,704,705,\cdots,18277,18278 were respectively given the names aaa, aab, aac, ..., zzy, zzz;

the dogs numbered 18279,18280,18281,\cdots,475253,475254 were respectively given the names aaaa, aaab, aaac, ..., zzzy, zzzz;

the dogs numbered 475255,475256,\cdots were respectively given the names aaaaa, aaaab, ...;

and so on.

To sum it up, the dogs numbered 1, 2, \cdots were respectively given the following names:

a, b, ..., z, aa, ab, ..., az, ba, bb, ..., bz, ..., za, zb, ..., zz, aaa, aab, ..., aaz, aba, abb, ..., abz, ..., zzz, aaaa, ...

Now, Roger asks you:

"What is the name for the dog numbered N?"

Constraints

N is an integer.

1 \leq N \leq 1000000000000001

Input

Input is given from Standard Input in the following format:

N

Output

Print the answer to Roger's question as a string consisting of lowercase English letters.

Sample Input 1

2

Sample Output 1

b

Sample Input 2

27

Sample Output 2

aa

Sample Input 3

123456789

Sample Output 3

jjddja

Solution in Java (OpenJDK 11.0.6) (judge verdict: Accepted)

//package ABC171;
import java.util.*;
import java.io.*;
class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		
		Scanner sc=new Scanner(System.in);
		long n=sc.nextLong();
		
		char ch[]=new char[27];
		for(int i=1;i<=26;i++)
		{
			ch[i]=(char)('a'+i-1);
		}
		HashMap<Long,Character> hm=new HashMap<>();
		
		for(long i=1;i<=26;i++)
		{
			hm.put(i,(char)('a'+i-1));
		}
		
		StringBuffer bf =new StringBuffer("");
		
		while(n>0)
		{
			long mod=n%26;
			if(n%26==0)
			{
				bf.append('z');
				n=n/26-1;
			}
			else
				{
				
				bf.append(hm.get(mod));
				n=n/26;
				}
			
		}
		bf.reverse();
		System.out.println(bf.toString());
		//System.out.println(Arrays.toString(ch));
		

	}

}