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: Accepted)

#include<stdio.h>

int main(){
  long n;
  scanf("%ld",&n);
  long n2 = n;
  int d = 1;//number of digit
  long l = 26;//large
  while(l < n2){
    n2 = n2 - l;
    l = l * 26;
    d++;
  }
  n2 = n;
  l = 26;
  char name[d + 1];//name;
  int tmp;
  for(int i = d - 1;i >= 0;i--){
    tmp = n % 26;
    name[i] =  'a' + tmp - 1;
    if(tmp == 0){
      name[i] ='z';
      tmp = 26;
    }
    n = (n - tmp)/26;
  }
  for(int i = 0;i < d;i++){
    printf("%c",name[i]);
  }
  //printf("%s",name);
  printf("\n");
  return 0;
}