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 Go (1.14.1) (judge verdict: Wrong Answer)

package main

import (
	"fmt"
)
// QuickSort is sort algorithm
func quickSort(values []int) (ret []int) {
	if len(values)<2 {
		return values
	}
	pivot := values[0]
	
	left := []int{}
	right := []int{}
	for _,v := range values[1:] {
		if v>pivot {
			right = append(right, v)
		} else {
			left = append(left, v)
		}
	}
	left = quickSort(left)
	right = quickSort(right)
	ret = append(left, pivot)
	ret = append(ret, right...)
	return 
}	

func main() {
	var n int 
	fmt.Scan(&n)
	var r []rune
	for n>0 {
		n--
		r = append(r, rune('a'+n%26))
		n/=26
	}
	fmt.Println(string(r))
}