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())
ans = float('inf')
for i in range(1, N):
    j = N-i
    i_str = str(i)
    j_str = str(j)
    i_sum, j_sum = 0, 0
    for p in range(len(i_str)):
        i_sum += int(i_str[p])
    for q in range(len(j_str)):
        j_sum += int(j_str[q])
    ans = min(ans, i_sum+j_sum)

print(ans)