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 = input()
minsofar = 100000000

def sumofdigits(a):
    ans = 0
    for i in `a`:
        ans += int(i)
    return ans

for i in range(1, n):
    a = i
    b = n - a
    minsofar = min(minsofar, sumofdigits(a) + sumofdigits(b))

print minsofar