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
def calc(n):
    ans = 0
    while n > 0:
        ans += n % 10
        n /= 10
    return ans

n = int(raw_input())
mn = 100
for a in range(1, n/2+1):
    mn = min(mn, calc(a) + calc(n-a))
print mn
