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(input())

def digitsum(x):
	tmp = x
	ans = 0
	while tmp > 0:
		ans += tmp % 10
		tmp /= 10

	return ans

ans = float("inf")
for i in range(1,(n/2)+1):
	ans = min(ans,digitsum(i) + digitsum(n-i))

print ans