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<string>
#include<vector>
#include<queue>
#include <cmath>
#include<algorithm>
#include<stack>
#include<map>
#include<ctime>
#define rep(i,n) for (int i=0;i<n;i++)
//#include <bits/stdc++.h>
using namespace std;

const long long X=1000000000000001;

int main(){
    long long N;
    cin>>N;
    string moji="abcdefghijklmnopqrstuvwxyz";
    vector<char> x;
    vector<long int> y;
    long long n=26;
    int m=1;
    while(N>0){
        if (N>=n) N=N-n;
        else break;
        n=n*26;
        m++;
  //      y.push_back(s);
    //    x.push_back(moji[s-1]);
    }
    if(N==0){
        for (int i=0;i<m-1;i++) cout<<'z';
        cout<<endl;
        return 0;
    }
    N--;
    int s=N%26;
        N=N/26;
        x.push_back(moji[s]);
    while(N>0){
        int ss=N%26;
        N=N/26;
        x.push_back(moji[ss]);
    }
    int siz=x.size();
    for (int i=0;i<m;i++){
        if (i<siz) cout<<x[siz-i-1];
        else cout<<'a';
    }

   // for (int i=0;i<x.size();i++) cout<<x[x.size()-1-i];
    cout<<endl;
    return 0;
}