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 <stdio.h>
#include <inttypes.h>

int main(void) {
	uint64_t N;
	uint64_t capacity = 26, pc = 0, delta = 1;
	int gotiusanokokoa[1024];
	int sumipe = 0;
	int i;
	int count = 0;
	if (scanf("%" SCNu64, &N) != 1) return 1;
	if (N > 26) {
		int num;
		while (capacity < N) {
			pc = capacity;
			delta *= 26;
			capacity += delta * 26;
			count++;
		}
		num = (int)((N - pc - 1) / delta);
		putchar('a' + num);
		N -= pc + delta * num;
	}
	N--;
	do {
		gotiusanokokoa[sumipe++] = (int)(N % 26);
		N /= 26;
	} while (N > 0 || sumipe < count);
	for (i = sumipe - 1; i >= 0; i--) putchar('a' + gotiusanokokoa[i]);
	putchar('\n');
}