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 int long long
#define INT_MAX INT64_MAX
#define INT_MIN INT64_MIN
#define PI 3.14159265358979323846
#define CLK clock_t clk = clock();//Start of main
#define OCLK cerr << "Time (in ms): " << (double)(clock() - clk) * 1000.0 / CLOCKS_PER_SEC << '\n';//End of main
#define MOD 1000000007
/* DEFINE cout */
#define pln cout << "===============================\n"
#define on cout<<"\n"
#define os cout<<" "
#define o2(a,b) cout<<a<<" "<<b
#define o(a) cout << a
#define bitcount __builtin_popcount
/* DEFINE cout */
#define endl "\n"
#define fastio ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);//fastio
using namespace std;
struct hash_pair { // use pair as key in unordered_map<pair<int,int>,int,hash_pair>;
    template <class T1, class T2>
    size_t operator()(const pair<T1, T2>& p) const
    {
        auto hash1 = hash<T1>{}(p.first);
        auto hash2 = hash<T2>{}(p.second);
        return hash1 ^ hash2;
    }
};
bool prime[10000001];
int P=MOD-2;
int factorial[10000001]={0};
int powerFunction(int x,int y){
    int res = 1;
    int p = MOD;
    x = x % p;
    while (y > 0){
        if (y & 1)
            res = (res*x) % p;
        y = y>>1;
        x = (x*x) % p;
    }
    return res;
}
void sieveFunction(int maxLimit){
    memset(prime, true, sizeof(prime));
    prime[0] = prime[1]=false;
    for(int i=2; maxLimit >= i ; i++){
        if(prime[i]){
            for(int j=2*i ; maxLimit >= j ; j+=i)
                prime[j]=false;
        }
    }
}
void factorialFunction(int maxLimit){
    factorial[0]=1;
    for(int i=1 ; i <= maxLimit ; i++)
        factorial[i]=(factorial[i-1]*i)%MOD;
    return;
}
int gcd(int a, int b){
    if (b == 0)
        return a;
    return gcd(b, a % b);
}
signed main(){
    int n;
    cin >> n;
    n--;
    string ans = "";
    while(n > 0){
        ans.push_back(n%26 + 'a');
        n/=26;
        n--;
        if(n == 0){
            ans.push_back('a');
        }
    }
    reverse(ans.begin(), ans.end());
    cout << ans << endl;
}