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 C (GCC 9.2.1) (judge verdict: Wrong Answer)

// SPDX-License-Identifier: X11
// 2020-07-04

#include <stdio.h>
#include <stdlib.h>

#define ALPHA 26

int main(void) {
  const char diff = 'a';

  long long N;
  scanf("%lld", &N);

  int i = 1;
  long long p = ALPHA;
  while (1) {
    if (N <= p)
      break;
    N -= p;
    p *= ALPHA;
    i++;
  }

  char *s = malloc(i * sizeof(char));

  if (i > 1) {
    if (N > 0 && N % 26 == 0)
      s[i - 1] = 'z';
    else
      s[i - 1] = N % 26 + diff - 1;

    N /= 26;
  }
  else {
    s[0] = N + diff - 1;
  }
  i--;

  while (i > 0) {
    if (N > 0 && N % 26 == 0)
      s[i - 1] = 'z';
    else
      s[i - 1] = N % 26 + diff;

    N /= 26;
    i--;
  }

  printf("%s\n", s);
  free(s);
}