fn main() {
    let stdin = std::io::stdin();
    let mut buf = String::new();
    stdin.read_line(&mut buf).ok();

    let mut result: i32 = 0;
    for i in buf.as_str().chars() {
        result += match i {
            '0'..='9' => i as i32 - 48,
            _ => continue,
        }
    }

    println!("{}", result);
}