use proconio::{fastout, input};

#[fastout]
fn main() {
    input! {
        a: [u8],
    }

    println!("{}", output(solve(a)));
}

fn solve(a: Vec<u8>) -> u16 {
    let mut count_of = [0; 36];
    a.iter().for_each(|&a| count_of[a as usize] += 1);
    let count_of = count_of;
    a.into_iter()
        .filter(|&a| count_of[(a - 1) as usize] == 0)
        .map(|a| a as u16)
        .sum()
}

fn output(ans: u16) -> u16 {
    ans
}