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 PyPy3 (7.3.0) (judge verdict: Wrong Answer)

# import sys
# input = sys.stdin.readline
# import re
import itertools

def main():
    n = int(input())
    borders = {702: 'zz', 18278: 'zzz', 475254: 'zzzz', 12356630:'zzzzz', 321272406:'zzzzzz', 8353082582:'zzzzzzz', 217180147158:'zzzzzzzz', 5646683826134:'zzzzzzzzz'}
    if n in borders:
        print(borders[n])
        exit()
    v = 26
    for l in range(2, 15):
        v = (26 ** l) + v
        if v >= n:
            break
    s = 'abcdefghijklmnopqrstuvwxyz'
    a = ''
    while True:
        i = n % 26
        n //= 26
        a += s[i-1]
        if n == 0:
            break
    print(a[:l][::-1])



def count_tento(l, cur):
    count = 0
    for v in l:
        if v > cur:
            count += 1
    return count

def input_list():
    return list(map(int, input().split()))

def prime_factorize(n):
    a = []
    while n % 2 == 0:
        a.append(2)
        n //= 2
    f = 3
    while f * f <= n:
        if n % f == 0:
            a.append(f)
            n //= f
        else:
            f += 2
    if n != 1:
        a.append(n)
    return a

if __name__ == '__main__':
    main()