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: Accepted)

<?php

[$N ] = fscanf(STDIN, "%d");
$keta = 0;
$keta_value = 26;
while($N > 0){
    $keta++;
    if($N > 26**$keta){
        $N -= 26**$keta;
    }else{
        break;
    }


}
$ans = "";
for($i=0;$i<$keta;$i++){
    if($N === 0){
        $ans = "a".$ans;
    }else {
        $ts = $N % 26;
        if($ans === "") {
            if ($ts === 0) {
                $ts = 26;
            }
            $ans = chr(96 + $ts) . $ans;
        }else{
            $ans = chr(97 + $ts) . $ans;
        }
        $N = intdiv($N - $ts, 26);
    }
}
echo $ans;