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 <ext/pb_ds/assoc_container.hpp> 
 //#include <ext/pb_ds/tree_policy.hpp>
//#include <bits/stdc++.h>
#include <iostream>
#include <iomanip>
#include <sstream>
#include <cstring>
#include <vector>
#include <deque>
#include <queue>
#include <set>
#include <map>
#include <valarray>
#include <iterator>
#include <functional>
#include <limits>
#include <algorithm>
#include <numeric>
#include <cmath>
#include <cassert>
#include <unordered_map>
#include <unordered_set>
#include <stack>
using namespace std;
#define IOS ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
#define trace(x) cerr << #x << ": " << x << " " << endl;

typedef int64_t ll;
 
#define endl '\n'
#define int ll
ll mod=1e9+7;
ll mod1=1e9+5;
ll power(ll a,ll b)
{
    if(b==0) return 1;
    else if(b%2==0)
        return power(((((a)%mod)*((a)%mod))%mod),b/2)%mod;
    else return (((a)%mod)*(power(((((a)%mod)*((a)%mod))%mod),b/2)%mod))%mod;
}
inline ll inverse(ll a,ll md) {
  a %= md;
  if (a < 0) a += md;
  ll b = md, u = 0, v = 1;
  while (a) {
    ll t = b / a;
    b -= t * a; swap(a, b);
    u -= t * v; swap(u, v);
  }
  assert(b == 1);
  if (u < 0) u += md;
  return u;
}
  
  
 //using namespace __gnu_pbds;
 //#define ordered_set tree<pair<int,int>, null_type,less<pair<int,int>>, rb_tree_tag,tree_order_statistics_node_update>
//find_by_order(k)  returns iterator to kth element starting from 0;
//order_of_key(k) returns count of elements strictly smaller than k;
//erase,insert same as normal set
// mt19937 mrand(chrono::high_resolution_clock::now().time_since_epoch().count()); for randomized solution
const int ce=1e9+7;
ll fast_mod(ll input)
{
    return input < ce ? input : input%ce;
}
int fre[100001];
int co[11];
int n,k;
int f[100001];
int maxi;
int dp[501][5001];
int solve(int i,int rem)
{
	if(rem==0)
		return 0;
	if(i==maxi)
		return 0;
	int &res=dp[i][rem];
	if(res!=-1)
		return res;
	res=0;
	for(int j=1;j<=min(rem,k);j++)
	{
		res=max(res,co[j]+solve(i+1,rem-j));
	}
	return res;
}
int32_t main()
{
    IOS
   
    
    int n;
    cin>>n;
    vector<int> v;
    while(n)
    {
    	if(n%26==0)
    	{
    		v.push_back(26);
    		n-=26;
    		n/=26;
    		continue;
    	}
    	v.push_back(n%26);
    	n/=26;
    }
    reverse(v.begin(),v.end());
    for(int i=0;i<v.size();i++)
    {
    	if(v[i]==0)
    	{
    		cout<<"z";
    	}
    	else
    	{
    		cout<<(char)('a'+v[i]-1);
    	}
    }

}