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 Ruby (2.7.1) (judge verdict: Accepted)

N = gets.chomp.to_i

ts = [0] * 12
name = []
count = 0
m = N
eigo = [*"a".."z"]
eigo.unshift("z")

(1..11).each do |i|
  ts[i] = (26 ** i)
end

while m > ts[count]
  m -= ts[count]
  count += 1
end

mozisu = count
# mozisu桁のm番目

while count > 0
  count -= 1
  if count > 0
    name[mozisu - count - 1] = (m / ts[count])
    m %= ts[count]
    if m != 0
      name[mozisu - count - 1] += 1
    end
  else
    name[mozisu - 1] = m
  end
end

(0...mozisu).each do |j|
  v = name[j]
  name[j] = eigo[v]
end

puts name.join