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)

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <cstdlib>
#include <cmath>
#include <vector>
#include <set>
#include <string>
#include <map>
#include <list>
#include <queue>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <utility>
using namespace std;

typedef unsigned int uint;
typedef long long int64;
typedef unsigned long long uint64;
typedef pair<int, int> ii;
typedef pair<int64, int64> int64int64;
typedef vector<int> vint;
typedef vector<int64> vint64;
typedef vector<uint64> vuint64;
typedef vector<vint> vvint;
typedef vector<vint64> vvint64;
typedef vector<vuint64> vvuint64;
typedef vector<ii> vii;
typedef vector<vector<ii>> vvii;

#define mp make_pair
#define pb push_back
#define ALL(a) a.begin(), a.end()
#define fi first
#define se second
#define fori(n) for(int i = 0; i < n; ++i)
#define forj(n) for(int j = 0; j < n; ++j)
#define fork(n) for(int k = 0; k < n; ++k)
#define INF9 (int64)(1e9)
#define INF18 (int64)(1e18)

template<typename T>
struct compF{
	bool operator()(const pair<T, T> &a, const pair<T, T> &b){
		return a.first < b.first;
	}
};

template<typename T>
struct compS{
	bool operator()(const pair<T, T> &a, const pair<T, T> &b){
		return a.second < b.second;
	}
};

template<typename T>
void printMatrix(const string &txt, vector<vector<T>> &a){
	cout << txt;
	fori(a.size()){
		forj(a[i].size())
			cout << a[i][j] << ' ';

		cout << endl;
	}
}

template<typename T>
void printVector(const string &txt, vector<T> &a){
	cout << txt;
	for (int i = 0; i < a.size(); ++i)
		cout << a[i] << ' ';
	cout << endl;
}

template<typename T>
void readVector(int n, vector<T> &a){
	if (a.size() < n)
		a.resize(n);

	fori(n) cin >> a[i];
}

template<typename T1, typename T2>
bool exist(map<T1, T2> &m, T1 x){
	if (m.find(x) == m.end())
		return false;

	return true;
}

int64 gcd(int64 a, int64 b){
	while (a != 0 && b != 0){
		if (b > a)
			b %= a;
		else
			a %= b;
	}

	return a + b;
}

int64 minFactor(int64 x){
	for (int64 i = 2; i * i <= x; ++i)
		if (x % i == 0)
			return i;

	return x;
}

int64 allFactors(int64 x, vint64 &prms, vint64 &prm_cnt){
	prms.clear();
	prm_cnt.clear();
	while (x > 1){
		int64 t = minFactor(x);
		prms.push_back(t);
		int s = prms.size() - 1;
		prm_cnt.push_back(0);
		while (x % t == 0){
			x /= t;
			++prm_cnt[s];
		}
	}

	return 0;
}

int main(){

	ios_base::sync_with_stdio(0);
	cin.tie();
	
	int n;
	cin >> n;

	vint res;
	while (n > 0){
		int c = (n - 1) % 26;
		res.push_back(c);

		n /= 26;
	}
	reverse(ALL(res));
	fori(res.size()) cout << char(res[i] + 'a');

	return 0;
}