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 <iostream>
#include <stdio.h>

#include <vector>
#include <cctype>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <string>

using namespace std;


int main()
{
    long long N;

    cin >> N;

    string pool[26]
        = {"z","a","b","c","d","e","f","g","h","i","j","k" ,"l","m","n","o","p","q","r","s","t","u","v","w","x","y"};

    long long num = N;
    int cou = 0;

    //何回割れるか分かる
    while (1) {
        if (num < 26) {
            break;
        }
        if (num == 0) {
            break;
        }
        num = num / 26;
        cou++;
        
    }
    
    vector<int> arr(cou+1);
   
    long long num2=N;
    int i = 0;
    while (1) {
        if (num2==0) {
            break;
        }
        arr[i] = num2 % 26;
        num2 = num2 / 26;
        i++;
    }
        
    reverse(arr.begin(), arr.end());
    int m = arr.size();
    for (int i = 0; i <m; i++) {
        cout << pool[arr[i]];
    }

    cout << endl;

    return 0;
}