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 <bits/stdc++.h>
#define endl "\n"
using namespace std;
typedef long long ll;
typedef vector<ll> vl;
typedef pair<ll, ll> PP;
#define rep(i, n) for(ll i = 0; i < ll(n); i++)
#define rrep(i, n) for(ll i = n - 1; i > -1; i--)
#define all(v) v.begin(), v.end()
#define pb push_back
#define fi first
#define se second
#define debug(V) rep(i, V.size()) cout << V[i] << " ";
const ll INF = (1LL << 61) - 1;
const ll MOD = 1000000007 /*998244353*/;
const ll MAX_N = 500010;
ll a, b, c, d, e, f, h, x, y, z, p, q, n, t, r, k, w, l, ans, i, j, u, v;
string S, T;
vl A, B;
void input() { cin >> n; }
void solve() {
    while(n) {
        S += "a";
        S.back() += (n % 26 - 1);
        n /= 26;
    }
    reverse(all(S));
    cout << S << endl;
}
int main() {
    // cout<<fixed<<setprecision(15);
    cin.tie(0);
    ios::sync_with_stdio(false);
    input();
    solve();
}