use std::io;

macro_rules! parse_input {
   ($x:expr, $t:ident) => ($x.trim().parse::<$t>().unwrap())
}

macro_rules! parse_inputs {
   ($x:expr, $t:ident) => (
       $x.trim()
       .split_whitespace()
       .map(|s| s.parse::<$t>().unwrap())
       .collect::<Vec<$t>>()
   )
}

macro_rules! print_err {
   ($($arg:tt)*) => (
       {
           use std::io::Write;
           writeln!(&mut ::std::io::stderr(), $($arg)*).ok();
       }
   )
}

fn cww(a: i64, b: i64, c: i64) -> i64 {
    let mut x = -1;
    if a != 0 && a != b && b == c {
        x = a * 100 + b * 10 + c;
    }
    x
}

fn main() {
    let mut input_line = String::new();
    io::stdin().read_line(&mut input_line).unwrap();
    let s = input_line.trim().bytes().map(|x| (x as i64) - 48).collect::<Vec<i64>>();
    let n = s.len();
    let mut dp = vec![-1; 1 << n];
    dp[0] = 0;

    for state in 0..(1 << n) {
        if dp[state] == -1 {
            continue;
        }
        for i in 0..n {
            for j in (i + 1)..n {
                for k in (j + 1)..n {
                    if ((state >> i) & 1) | ((state >> j) & 1) | ((state >> k) & 1) != 0 {
                        continue;
                    }
                    let x = cww(s[i], s[j], s[k]);
                    if x != -1 {
                        let nxstate = state | (1 << i) | (1 << j) | (1 << k);
                        if dp[nxstate] < dp[state] + x {
                            dp[nxstate] = dp[state] + x
                        } else {
                            dp[nxstate] = dp[nxstate]
                        };
                    }
                }
            }
        }
    }
    println!("{}", dp.iter().max().unwrap());
}