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 Fortran (GNU Fortran 9.2.1) (judge verdict: Accepted)

program c171

implicit none
integer(16) :: n, m, l
integer :: i, j
character(len=12) :: a, b

read *, n

i = 0

do while (n > 26)
 i = i + 1
 m = mod(n,26)
 if (m == 0) then
   m = 26
 end if
  a(i:i) = char(96 + m)
  n = n - m
  n = n / 26
end do

a(i+1:i+1) = char(96 + n)

do j = 1, i+1
 b(j:j) = a(i+2-j:i+2-j)
end do

if (i+1 == 12) then
 print '(A12)', trim(adjustl(b))
else if (i+1 == 11) then
 print '(A11)', trim(adjustl(b))
else if (i+1 == 10) then
 print '(A10)', trim(adjustl(b))
else if (i+1 == 9) then
 print '(A9)', trim(adjustl(b))
else if (i+1 == 8) then
 print '(A8)', trim(adjustl(b))
else if (i+1 == 7) then
 print '(A7)', trim(adjustl(b))
else if (i+1 == 6) then
 print '(A6)', trim(adjustl(b))
else if (i+1 == 5) then
 print '(A5)', trim(adjustl(b))
else if (i+1 == 4) then
 print '(A4)', trim(adjustl(b))
else if (i+1 == 3) then
 print '(A3)', trim(adjustl(b))
else if (i+1 == 2) then
 print '(A2)', trim(adjustl(b))
else
 print '(A1)', trim(adjustl(b))
end if

end program c171