use std::io;

fn main() {
    let mut s = String::new();
    io::stdin().read_line(&mut s).unwrap();

    let sum: u32 = s.trim()
        .bytes()
        .filter(|&b| b >= b'0' && b <= b'9')
        .map(|b| (b - b'0') as u32)
        .sum();
    println!("{}", sum);
}