fn main() {
    let mut input = String::new();
    std::io::Read::read_to_string(&mut std::io::stdin(), &mut input).ok();
    let input: Vec<u64> = input
        .split_whitespace()
        .map(|n| n.parse().unwrap())
        .collect();

    let n_total_votes: u64 = input[1..].iter().sum();
    let n_confiscated = input[1..]
        .iter()
        .filter(|&n| 10 * n <= n_total_votes)
        .count();

    println!("{}", 30 * n_confiscated);
}