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 main():
    n = input()
    best = float('inf')
    for a in range(1, n//2 + 1):
        b = n - a
        s = sum(map(int, '%i%i' % (a, b)))
        best = min(best, s)
    print best

if __name__ == '__main__':
    main()
