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
n=int(raw_input())
ret=[]
for y in range(n/2):
	a=y+1
	b=n-a
	r1 = 0
	r2 = 0
	for i in str(a):
		r1 += int(i)
	for x in str(b):
		r2 += int(x)
	r=r1+r2
	ret.append(r)
print min(ret)