use std::collections::BTreeSet;

fn main() {
    let (n,m) : (usize,usize) = input_t();
    let a : Vec<usize> = input_vec();

    let a : BTreeSet<_> = a.into_iter().collect();
    let mut ans = 0;
    let mut cnt = vec![0; n+1];
    for i in (1..=n).rev() {
        if cnt[i]%2 == 0 && !a.contains(&i) {
            ans += 1;
            continue
        }

        for j in (1..i) {
            if j*j > i { break }
            if i%j != 0 { continue }
            cnt[j] += 1;
            if i/j != j { cnt[i/j] += 1; }
        }
    }

    println!("{}", ans);
}

#[allow(dead_code)] fn input<T: std::str::FromStr>() -> T { let mut s = String::new(); std::io::stdin().read_line(&mut s).ok(); s.trim().parse().ok().unwrap() } #[allow(dead_code)] fn input_t<T: std::str::FromStr, U: std::str::FromStr>() -> (T, U) { let mut s = String::new(); std::io::stdin().read_line(&mut s).ok(); let s = s.trim().split_whitespace().collect::<Vec<&str>>(); (s[0].parse().ok().unwrap(), s[1].parse().ok().unwrap()) } #[allow(dead_code)] fn input_t3<T1: std::str::FromStr, T2: std::str::FromStr, T3: std::str::FromStr>() -> (T1, T2, T3) { let mut s = String::new(); std::io::stdin().read_line(&mut s).ok(); let s = s.trim().split_whitespace().collect::<Vec<&str>>(); (s[0].parse().ok().unwrap(), s[1].parse().ok().unwrap(), s[2].parse().ok().unwrap()) } #[allow(dead_code)] fn input_t4<T1: std::str::FromStr, T2: std::str::FromStr, T3: std::str::FromStr, T4: std::str::FromStr>() -> (T1, T2, T3, T4) { let mut s = String::new(); std::io::stdin().read_line(&mut s).ok(); let s = s.trim().split_whitespace().collect::<Vec<&str>>(); (s[0].parse().ok().unwrap(), s[1].parse().ok().unwrap(), s[2].parse().ok().unwrap(), s[3].parse().ok().unwrap()) } #[allow(dead_code)] fn input_t5<T1: std::str::FromStr, T2: std::str::FromStr, T3: std::str::FromStr, T4: std::str::FromStr, T5: std::str::FromStr>() -> (T1, T2, T3, T4, T5) { let mut s = String::new(); std::io::stdin().read_line(&mut s).ok(); let s = s.trim().split_whitespace().collect::<Vec<&str>>(); (s[0].parse().ok().unwrap(), s[1].parse().ok().unwrap(), s[2].parse().ok().unwrap(), s[3].parse().ok().unwrap(), s[4].parse().ok().unwrap()) } #[allow(dead_code)] fn input_vec<T: std::str::FromStr>() -> Vec<T> { let mut s = String::new(); std::io::stdin().read_line(&mut s).ok(); s.trim().split_whitespace().map(|s| s.parse().ok().unwrap()).collect() }