use std::{collections::HashSet, io};

fn main() {
    io::stdin().read_line(&mut String::new()).ok();
    let mut a = String::new();
    io::stdin().read_line(&mut a).ok();
    let mut a = a
        .split_whitespace()
        .map(|n| n.parse::<u64>().unwrap())
        .collect::<Vec<_>>();

    a.sort_unstable();

    let duplicates = a
        .windows(2)
        .filter_map(|n| if n[0] == n[1] { Some(n[0]) } else { None })
        .collect::<HashSet<_>>();

    a.retain(|n| !duplicates.contains(n));

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