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 Rust (1.15.1) (judge verdict: Accepted)

use std::io::stdin;

fn main() {
    let mut st = String::new();
    stdin().read_line(&mut st).unwrap();
    let n:Vec<char> = st.trim().chars().collect();
    let mut r:Vec<i32> = Vec::new();
    for i in 0..n.len() {
        r.push(n[i] as i32);
        let x:&mut i32 = r.last_mut().unwrap();
        *x -= 48;
    }
    let mut result = 0;
    for i in r {
        result += i;
    };
    if result == 1 {
        result = 10;
    };
    println!("{}", result);
}