use std::collections::HashSet;

fn main() {
    let mut n = String::new();
    std::io::stdin().read_line(&mut n).ok();
    let n: Vec<char> = n.trim().chars().collect();

    let nlen = n.len();
    if nlen < 3 {
        println!("0");
        return;
    }
    let mut pairs: Vec<(usize, HashSet<usize>)> = vec![];
    for i in 0..nlen {
        for j in i+1..nlen {
            for k in j+1..nlen {
                if n[i] != '0' && n[j] == n[k] && n[i] != n[j] {
                    let limit = pairs.len();
                    let mut pair = HashSet::new();
                    pair.insert(i);
                    pair.insert(j);
                    pair.insert(k);
                    let val: usize = vec![n[i],n[j],n[k]].into_iter().collect::<String>().parse().unwrap();
                    for idx in 0..limit {
                        if (pairs[idx].1).intersection(&pair).count() == 0 {
                            let mut base = pairs[idx].clone();
                            pair.iter().for_each(|v| { (base.1).insert(*v); });
                            base.0 += val;
                            pairs.push(base);
                        }
                    }
                    pairs.push((val, pair));
                }
            }
        }
    }
    println!("{}", pairs.iter().map(|p| p.0).max().unwrap_or(0usize));
}