#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
typedef int64_t lint;
#define rep(i, n) for(int i=0; i<n; i++)
#define repx(i, l, n) for(int i=l; i<n; i++)
#define all(v) v.begin(), v.end()
#define show(x) cout << #x << ": " << x << endl;
#define list(x) cout << #x << ": " << x << "  ";
#define pb push_back
using vi = vector<lint>;
using vvi = vector<vector<lint>>;
template<class T> inline void vin(vector<T>& v) { rep(i, v.size()) cin >> v.at(i); }
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
template<class T> inline void drop(T x) { cout << x << endl; exit(0); }
template<class T> void vout(vector<T> v) { rep(i, v.size()) { cout << v.at(i) << ' '; } cout << endl; }
constexpr lint LINF = LLONG_MAX/2;
vector<lint> divisor(lint n) {
	vector<lint> v;
	for (lint i = 1; i*i <= n; i++) {
		if (n % i == 0) {
			v.push_back(i);
			if (i*i != n) v.push_back(n/i);
		}
	}
	sort(v.begin(), v.end());
	return v;
}

int main() {
	lint N, M;
	cin >> N >> M;
	vi v(M);
	vin(v);

	lint a=0, b=0, c=0, x, y, z;
	set<lint> s;
	rep(i, M) s.insert(v[i]);
	vi w(N+1);
	for (size_t i = N; i > 0; i--) {
		vi t = divisor(i);
		rep(j, t.size()) w[t[j]] ^= 1;
		if ((w[i] && !s.count(i)) || (!w[i] && s.count(i))) {
			b++;
			rep(j, t.size()) w[t[j]] ^= 1;
		}
	}
	std::cout << b << '\n';
}