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 <fsociety>
#include <cmath>
#include <deque>
#include <algorithm>
#include <iterator>
#include <list>
#include <map>
#include <unordered_map>
#include <queue>
#include <set>
#include <unordered_set>
#include <stack>
#include <string>
#include <vector>
#include <fstream>
#include <iostream>
#include <iomanip> 
#include <stdio.h>
//end of libraries ;
// freopen("input.txt","r",stdin);
// freopen("output.txt","w",stdout);
// ll lmax(ll o , ll w) {if(o>w)return o; return w;}
// ll lmin(ll o , ll w) {if(o<w)return o; return w;}
#define LNF 3999999999999999999
#define INF 999999999
#define N 3000003
#define PI 3.14159265359
#define endl "\n"
#define F first
#define S second
#define pb push_back
#define ll long long
#define all(c) (c).begin(),(c).end()
#define sz(c) (int)(c).size()
#define mkp(a,b) make_pair(a,b)
#define fcin ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0);
using namespace std;
ll n;
string ans;
int main(){
fcin;
    cin >> n;
    ll p = 1;
    while(n){
        if( (n/p) % 26 == 0){
            ans = 'z' + ans;
            n-=p;
        }
        else{
        char x = ('a' + (n/p)%26 - 1);
        ans = x + ans;
        }
        p*=26;
        if(p>n) break;
    }
    cout << ans << '\n';

}