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".

Examples

Input

15


Output

6


Input

100000


Output

10
#!/usr/bin/python
# -*- coding: utf-8 -*-

n=int(raw_input())
maxv=n
for a in xrange(1,n):
  b=n-a
  if a>b: break
  sa=sum([int(x) for x in str(a)])
  sb=sum([int(x) for x in str(b)])
  maxv=min(maxv, sa+sb)
print(maxv)