Problem:
Score : 200 points

Problem Statement

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".

Sample Input 1

15

Sample Output 1

6

When A=2 and B=13, the sums of their digits are 2 and 4, which minimizes the value in question.

Sample Input 2

100000

Sample Output 2

10

Solution in Python (3.8.2) (judge verdict: Accepted)

n = int(input())
absum = []
for a in range(1,n):
    b = n-a
    asum = 0
    bsum = 0
    alen = len(str(a))
    blen = len(str(b))
    for j in range(alen):
        a0 = (a//(10**j)) % 10
        asum = asum + a0
    for k in range(blen):
        b0 = (b//(10**k)) % 10
        bsum = bsum + b0
    absum.append(asum+bsum)
print(min(absum))