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)

#include<bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < n; i++)
 
using namespace std;

int main(){
  long long n;
  cin >> n;
  stack<char> S;
  while(n!=0){
    long long s;
    s = n%26;
    char x;
    if(s==1) x = 'a';
    if(s==2) x = 'b';
    if(s==3) x = 'c';
    if(s==4) x = 'd';
    if(s==5) x = 'e';
    if(s==6) x = 'f';
    if(s==7) x = 'g';
    if(s==8) x = 'h';
    if(s==9) x = 'i';
    if(s==10) x = 'j';
    if(s==11) x = 'k';
    if(s==12) x ='l';
    if(s==13) x ='m';
    if(s==14) x ='n';
    if(s==15) x ='o';
    if(s==16) x ='p';
    if(s==17) x ='q';
    if(s==18) x ='r';
    if(s==19) x ='s';
    if(s==20) x ='t';
    if(s==21) x ='u';
    if(s==22) x ='v';
    if(s==23) x ='w';
    if(s==24) x ='x';
    if(s==24) x ='y';
    if(s==26) x ='z';
    S.push(x);
    n = (n - s)/26;
  }
  while(!S.empty()){
    cout << S.top();
    S.pop();
  }
}