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 (3.4.3) (judge verdict: Wrong Answer)

# -*- coding: utf-8 -*-

def sum_digits(val):
    work = 0
    while True:
        work += val % 10
        val //= 10
        if val == 0:
            break
    return work
   
n = int(input())

values = []
for a in range(2, n + 1):
    b = n - a
    if b < 2:
        continue
    print("{}, {} / {}, {}".format(a, sum_digits(a), b, sum_digits(b)))
    values.append(sum_digits(a) + sum_digits(b))

values.sort()
# print(values)
print("0" if len(values) == 0 else values[0])