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: Wrong Answer)

require 'pp'
$DEBUG ? define_method(:dpp){|e|pp e} : define_method(:dpp){|e|}

# 入力値を数値で返却する
def gets_i()
  gets.chomp.to_i
end
n = gets_i

s = n.to_s(26)
ans = []

s.chars.each do |c|
  if c == "1"
    ans.push("a")
  elsif c == "2"
    ans.push("b")
  elsif c == "3"
    ans.push("c")
  elsif c == "4"
    ans.push("d")
  elsif c == "5"
    ans.push("e")
  elsif c == "6"
    ans.push("f")
  elsif c == "7"
    ans.push("g")
  elsif c == "8"
    ans.push("h")
  elsif c == "9"
    ans.push("i")
  elsif c == "a"
    ans.push("j")
  elsif c == "b"
    ans.push("k")
  elsif c == "c"
    ans.push("l")
  elsif c == "d"
    ans.push("m")
  elsif c == "e"
    ans.push("n")
  elsif c == "f"
    ans.push("o")
  elsif c == "g"
    ans.push("p")
  elsif c == "h"
    ans.push("q")
  elsif c == "i"
    ans.push("r")
  elsif c == "j"
    ans.push("s")
  elsif c == "k"
    ans.push("t")
  elsif c == "l"
    ans.push("u")
  elsif c == "m"
    ans.push("v")
  elsif c == "n"
    ans.push("w")
  elsif c == "o"
    ans.push("x")
  elsif c == "p"
    ans.push("y")
  elsif c == "q"
    ans.push("z")
  end
end

puts ans.join