use std::io::{self, BufReader, BufWriter, Read, Write};

fn main() {
    let stdin = io::stdin();
    let mut stdin = BufReader::new(stdin.lock());
    let stdout = io::stdout();
    let mut stdout = BufWriter::new(stdout.lock());

    let mut buf = String::new();
    stdin.read_to_string(&mut buf).unwrap();

    let sum: u32 = buf
        .bytes()
        .filter(|b| b.is_ascii_digit())
        .map(|b| b as u32 - 48)
        .sum();
    writeln!(&mut stdout, "{}", sum).unwrap();
}