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 Python (3.8.2) (judge verdict: Wrong Answer)

N = int(input())
moji = [chr(i) for i in range(97, 97+26)]

lst = [0]
n = 0
for i in range(1,13):
    n = n + 26 ** i
    lst.append(n)

#桁数の確定
keta = 0
for i in range(len(lst)):
    if N <= lst[i]:
        keta = i
        break

num = []
ketax = keta
for _ in range(keta):
    syo = N // (26 ** (ketax - 1))
    amari = N % (26 ** (ketax - 1))
    if syo == 27:
        syo = 26
        amari = 26 ** (ketax - 1)
    num.append(syo)
    N = amari
    ketax -= 1

ans = ''
for i in range(len(num)):
    ans += moji[num[i]-1]
print(ans)