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 <iostream>
#include <fstream>
#include <cstdio>
#include <vector>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <stack>
#include <queue>
#include <algorithm>
#include <string.h>
#include <string>
#include <math.h>
#include <iomanip>
using namespace std;

#define SORT(v) sort((v).begin(), (v).end())
#define RSORT(v) sort((v).rbegin(), (v).rend())
#define pb push_back

typedef pair<int, int> pii;
typedef long long ll;
typedef unsigned long long ull;

const int mod = 1e9 + 7;
const int mod2 = 998244353;

ll exp(ll taban, ll us, ll md) {
    ll carpan = taban % md;
	if(carpan == 0) return 0;
    ll temp = us;
    ll res = 1;
    while(temp){
        if(temp % 2) res = (res*carpan) % md;
        temp /= 2;
        carpan = (carpan*carpan) % md;
    }
    return res;
}
 
ll ebob(ll a, ll b){
    if(!a)return b;
    return ebob(b%a, a);
}

ll ekok(ll a, ll b){
    return (a*b)/ebob(a, b);
}

vector<ll> fact;
vector<ll> inv_fact;
void fact_init(int n){
	fact.resize(n+5);
	inv_fact.resize(n+5);
	fact[0] = inv_fact[0] = 1;
	for(int i = 1; i <= n; i++){
		fact[i] = (fact[i-1] * i) % mod;
		inv_fact[i] = exp(fact[i], mod-2, mod);
	}
}

ll komb(ll a, ll b){
	if(a < b) return 0;
	return fact[a] * (inv_fact[a-b] * inv_fact[b] % mod) % mod;
}

const int N = 5e3+5;

int main(){
	ios::sync_with_stdio(false); cin.tie(NULL);
	ll n; cin>>n;
	string res;
	while(n){
		res += n%26 + 'a' - 1;
		n /= 26;
	}
	reverse(res.begin(), res.end());
	cout<<res;
}