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: Accepted)

N = int(input())

D = 26
lst = []
while N > 0:
    # c = N%26
    # if c == 0:
    #     ans += 'z'
    # else:
    #     ans += chr(ord('a') + (N%26) - 1)

    lst.append(N%D)
    N //= D

# print(lst)
ans = ""
z = False
for i in range(len(lst)):
    # print(i)
    if i == len(lst)-1 and lst[i] == 0:
        break

    if lst[i] == 0:
        ans += 'z'
        while lst[i+1] == 0:
            lst[i+1] = 25
            i+=1
        lst[i+1] -= 1
    else:
        ans += chr(ord('a') - 1 + lst[i])


# for c in enulst:
#     if c == 0:
#         z=True
#     else:
#         if z:
#             ans += chr(ord('z') + 1 - c)
#         else:
#             ans += chr(ord('a') - 1 + c)

# print(lst)
# print("rev:", list(reversed(lst)))
# print(ans)
print("".join(list(reversed(ans))))