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 f(x):
    res = 0
    while x > 0:
        res += x % 10
        x /= 10
    return res

def solve(n):
    return min([f(a) + f(n-a) for a in range(1,n)])

assert solve(15) == 6
assert solve(100000) == 10, solve(100000)
n = input()
print solve(n)