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 int long long
#define ld long double
#define pb push_back
#define mp make_pair
#define f first
#define s second
#define all(x) x.begin(),x.end()
#define LOL cout<<'\n';
#define MOD 1000000007
#define sz(x) ((int)x.size())
#define INF LONG_LONG_MAX
#define MINF LONG_LONG_MIN

void solve(){
  int n; cin>>n; 
  int s=26;
  int l=1;
  while(n>s){
    n-=s;
    s*=26;
    l++;
  }
  string ans(l,'0');
  n--;
  for(int i=l-1 ; i>=0 ; i--){
    ans[i]=n%26+'a';
    n/=26;
  }
  cout<<ans;LOL
}

signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0); cout.tie(0);
  solve();
  return 0;
}