fn main() {
    let s : Vec<_> = input::<String>().chars().collect();

    let ans = s.iter().fold(0, |acc, &v| acc + if v.is_digit(10) {(v as u8 - b'0') as u64} else {0});
    println!("{}", ans);
}



#[allow(dead_code)]
fn input<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}

#[allow(dead_code)]
fn input_t<T: std::str::FromStr, U: std::str::FromStr>() -> (T, U) {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    let s = s.trim().split_whitespace().collect::<Vec<&str>>();
    (s[0].parse().ok().unwrap(), s[1].parse().ok().unwrap())
}

#[allow(dead_code)]
fn input_t3<T1: std::str::FromStr, T2: std::str::FromStr, T3: std::str::FromStr>() -> (T1, T2, T3) {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    let s = s.trim().split_whitespace().collect::<Vec<&str>>();
    (s[0].parse().ok().unwrap(), s[1].parse().ok().unwrap(), s[2].parse().ok().unwrap())
}

#[allow(dead_code)]
fn input_t4<T1: std::str::FromStr, T2: std::str::FromStr, T3: std::str::FromStr, T4: std::str::FromStr>() -> (T1, T2, T3, T4) {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    let s = s.trim().split_whitespace().collect::<Vec<&str>>();
    (s[0].parse().ok().unwrap(), s[1].parse().ok().unwrap(), s[2].parse().ok().unwrap(), s[3].parse().ok().unwrap())
}

#[allow(dead_code)]
fn input_t5<T1: std::str::FromStr, T2: std::str::FromStr, T3: std::str::FromStr, T4: std::str::FromStr, T5: std::str::FromStr>() -> (T1, T2, T3, T4, T5) {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    let s = s.trim().split_whitespace().collect::<Vec<&str>>();
    (s[0].parse().ok().unwrap(), s[1].parse().ok().unwrap(), s[2].parse().ok().unwrap(), s[3].parse().ok().unwrap(), s[4].parse().ok().unwrap())
}

#[allow(dead_code)]
fn input_vec<T: std::str::FromStr>() -> Vec<T> {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().split_whitespace().map(|s| s.parse().ok().unwrap()).collect()
}