fn main() {
    let (n, k) = {
        let mut line = String::new();
        std::io::stdin().read_line(&mut line).unwrap();
        let mut iter = line.split_whitespace();
        (
            iter.next().unwrap().parse::<usize>().unwrap(),
            iter.next().unwrap().parse::<usize>().unwrap(),
        )
    };
    let aa: Vec<_> = {
        let mut line = String::new();
        std::io::stdin().read_line(&mut line).unwrap();
        line.split_whitespace()
            .map(|x| x.parse::<usize>().unwrap() - 1)
            .collect()
    };

    let mut counts = vec![0_usize; n];
    for &a in &aa {
        counts[a] += 1;
    }
    counts.sort_unstable();

    let mut rem = k;
    let mut cards = vec![];
    for &cnt in counts.iter().rev() {
        if cnt >= rem {
            cards.push(rem);

            break;
        }

        cards.push(cnt);
        rem -= cnt;
    }

    println!("{}", cards.len());
}