Problem:
Score : 200 points

Problem Statement

Takahashi has two positive integers A and B.

It is known that A plus B equals N.
Find the minimum possible value of "the sum of the digits of A" plus "the sum of the digits of B" (in base 10).

Constraints

2 ≤ N ≤ 10^5

N is an integer.

Input

Input is given from Standard Input in the following format:

N

Output

Print the minimum possible value of "the sum of the digits of A" plus "the sum of the digits of B".

Sample Input 1

15

Sample Output 1

6

When A=2 and B=13, the sums of their digits are 2 and 4, which minimizes the value in question.

Sample Input 2

100000

Sample Output 2

10

Solution in Fortran (gfortran v4.8.4) (judge verdict: Accepted)

program sum
implicit none
integer::n, a, b, c, d ,e ,ans
 
read(5,*)n
 
 if(n==10.or.n==100.or.n==1000.or.n==10000.or.n==100000) then  
  ans=10
 else
  a=n/10000
  b=n/1000-10*a
  c=n/100-10*b-100*a
  d=n/10-10*c-100*b-1000*a
  e=n-10*d-100*c-1000*b-10000*a
  ans=a+b+c+d+e
endif
 
write(6,*)ans
 
end program sum