use std::io::{self, BufRead};

fn get_lines() -> Vec<String> {
    let stdin = io::stdin();
    let lines: Vec<String> = stdin.lock().lines().map(|l| l.unwrap()).collect();
    return lines;
}

fn main(){
	let s = &get_lines()[0];
    let mut sum = 0;
    for c in s.chars() {
        if c.is_digit(10) {
            let n = c.to_digit(10).unwrap();
            sum += n;
        }
    }
    println!("{}", sum);
}