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())
a = 1
best = 999999999999999
def score(a, b):
    return sum([int(c) for c in str(a) + str(b)])
while a <= n/2:
    b = n - a
    best = min(best, score(a, b))
    a += 1
print best
