use std::io::*;
use std::str::*;

fn read<T: FromStr>(sl: &mut StdinLock) -> Option<T> {
    let s = sl.by_ref().bytes().map(|c| c.unwrap() as char)
        .skip_while(|c| c.is_whitespace())
        .take_while(|c| !c.is_whitespace())
        .collect::<String>();

    s.parse::<T>().ok()
}

fn to_number(c: char) -> i32 {
    if c.is_digit(10) { c.to_digit(10).unwrap() as i32 } else { 0 }
}

fn run(sl: &mut StdinLock) {
    let s = read::<String>(sl).unwrap();
    let sum = s.chars().map(to_number).sum::<i32>();
    println!("{}", sum);
}

fn main() {
    let s = stdin();
    let mut sl = s.lock();
    run(&mut sl);
}