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 PHP (7.4.4) (judge verdict: Wrong Answer)

<?php
$n=trim(fgets(STDIN));
$a=array(1,27,703,18279,475255,12356631,321272407,8353082583,217180147159,5646683826135,146813779479511,3817158266467287);
$i=0;
while($a[$i]<=$n){
  if($a[$i]==$n){
    echo str_repeat('a',$i+1);
    exit;
  }
  ++$i;
}
$ans=str_repeat('a',$i);
--$i;
$abc='abcdefghijklmnopqrstuvwxyz';
while($n>0){
  $r=$n%26;
  $n=($n-$r)/26;
  $ans[$i]=$abc[$r-1];
  --$i;
}
echo "$ans\n";