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: Output Limit Exceeded)

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

const long long int MOD = 26;

int main()
{
	long long int n;
	scanf("%lld", &n);

	long long int pre = -1;

	while (1)
	{
		if (n < MOD)
		{
			printf("%c", 'a' - 1 + n);
			break;
		}

		int cnt = 0;
		long long int t = 1;
		while (t * MOD < n)
		{
			t *= MOD;
			cnt++;
		}

		if (pre != -1 && cnt != pre - 1)
		{
			for (int i = pre - 1; i <= cnt + 1; i--)
			{
				printf("%c", 'a');
			}
		}
		pre = cnt;

		printf("%c", 'a' - 1 + n / t);
		n %= t;
	}

	return 0;
}