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<vector>
#include<cmath>
#include<algorithm>
#include<string>
#include<climits>
#include<stack>
#include<queue>
#include<unordered_map>
#include<map>
#include<set>

#define loopi(x,y) for(int i = x;i<(y);i++)
#define rloopi(x,y) for(int i = x;i>=(y);i--)
#define rloopj(x,y) for(int j = x;j>=(y);j--)
#define loopj(x,y) for(int j = x;j<(y);j++)


#define nl cout<<"\n";
#define ll long long int
using namespace std;
#define mod  1000000007


int main()
{
	ios :: sync_with_stdio(false);
	cin.tie(nullptr);

#ifndef ONLINE_JUDGE
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);
#endif

	ll n;
	cin >> n;

	ll dt = 26;
	int k = 1;

	while (dt < n)
	{
		n -= dt;
		dt *= 26;
		k++;
	}

	string ans;
	if (n == dt)
	{
		while (k)
		{
			ans += 'z';
			k--;
		}
	}
	else
	{
		dt /= 26;

		int c;
		int flag = 1;

		while (dt > 1)
		{
			if (n % dt == 0)
			{
				ans += 'a';
				flag = 0;
				k--;
				break;
			}
			c = n / dt;
			ans += char(int(c) + 97);
			n = n % dt;
			dt /= 26;
			k--;
		}

		if (flag == 0)
		{
			while (k)
			{
				ans += 'z';
				k--;
			}

		}
		else
		{
			ans += char(int(n) + 96);
		}
	}

	cout << ans;

	return 0;
}