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<iostream>
using namespace std;
//#include<math>
#include<algorithm>
#include<map>
//#include<pair>
#include<vector>
#include<set>
#include<stack>
#include<queue>
//priority_queue inside queue
#include<deque>
#define fast ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
#define nl '\n'
typedef long long ll;
typedef unsigned long long ull;
#define f(i,start,end) for(i=start;i<=end;i++)


bool isPrime(int n)
{
    for(int i=2; i*i<=n; i++)
    {
        if(n%i==0) return false;
    }
    return true;
}

string baseConvertFromDecimal(int base, ll n)
{
    string s = "";
    while(n!=0)
    {
        int rem = (n%base);
        if(rem!=0) s += 'a'-1 + rem;
        else s += 'z';
        n/=base;
        if(rem==0) n--;
    }
    reverse(s.begin(), s.end());
    return s;
}

int main()
{
fast;
//int t=0; cin >> t; while(t--) //testcases
{
    ll n; cin >> n;   
    
    string dog = baseConvertFromDecimal(26, n);
    
    cout << dog << nl;
}return 0;
}