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 <bits/stdc++.h>
  
using namespace std;
 
#define ll long long
#define uint unsigned int
#define ull  unsigned long long
#define pb push_back
#define mk make_pair
#define ins insert
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(),(x).rend()
#define X first
#define Y second
#define umap unordered_map
#define speed() ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0)
#define setvalue(d,s,e,n) for(int qwe = s; qwe < e; ++qwe) d[qwe] = n
#define mset multiset
#define pqueue priority_queue
   
        
const int  N = 2e5 + 314;
const int INF = 1e9;
const double PI = acos(-1);
const int MOD = 1e9 + 7;
const double eps = 1e-9;
const long long LINF = 1e18 + 3141;
ll n;
char z[26];
void solve(){
    cin >> n;
    string ans = "";
    while(n > 0) {
        ans = z[n % 26] + ans;
        if(n % 26 == 0)
            n --;
        n /= 26;
    }
    cout << ans;
}
 
int main(){
    speed();
    int t = 1;
    // cin >> t;
    z[0] = 'z';
    for(int i = 1; i < 26; ++i)
        z[i] = 'a' + i - 1;
    while(t--)solve();
}