use ac_library::Dsu;
use std::io::Read;

fn main() {
    let mut s = String::new();
    std::io::stdin().read_to_string(&mut s).unwrap();
    let mut it = s.split_ascii_whitespace().map(|x| x.parse::<usize>().unwrap());
    let n = it.next().unwrap();
    let m = it.next().unwrap();
    let mut d = Dsu::new(n);
    for _ in 0..m {
        let u = it.next().unwrap();
        let v = it.next().unwrap();
        d.merge(u, v);
    }
    println!("{}", (0..n).filter(|&i| d.leader(i) == i).count());
}