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 PyPy3 (7.3.0) (judge verdict: Accepted)

import sys
readline = sys.stdin.buffer.readline
def even(n): return 1 if n%2==0 else 0

n = int(readline())
ans = 10**18
for i in range(1,n):
    j = n-i
    s = str(i).rjust(6,"0")[::-1]
    t = str(j).rjust(6,"0")[::-1]
    res = 0
    for i,j in zip(s,t):
        res += int(i)+int(j)
    ans = min(res,ans)

print(ans)