#include <bits/stdc++.h>
using namespace std;

using ll = long long;
using VI = vector<int>;
using VVI = vector<vector<int>>;
using VVVI = vector<vector<vector<int>>>;
using VL = vector<ll>;
using VVL = vector<vector<ll>>;
using VVVL = vector<vector<vector<ll>>>;
using VD = vector<double>;
using VVD = vector<vector<double>>;
using VVVD = vector<vector<vector<double>>>;
using VB = vector<bool>;
using VVB = vector<vector<bool>>;
using P = pair<int, int>;
using VP = vector<P>;

#define REP(i, n) for (int i = 0; i < (int)(n); i++)
#define FOR(i, a, b) for (ll i = a; i < (ll)(b); i++)
#define ALL(a) (a).begin(),(a).end()

constexpr int INF = 1001001001;
constexpr ll LINF = 1001001001001001001ll;
constexpr int DX[] = {1, 0, -1, 0};
constexpr int DY[] = {0, 1, 0, -1};

template< typename T1, typename T2>
inline bool chmax(T1 &a, T2 b) {return a < b && (a = b, true); }
template< typename T1, typename T2>
inline bool chmin(T1 &a, T2 b) {return a > b && (a = b, true); }

const ll MOD = 998244353;

ll mod_pow(ll x, ll n, ll mod) {
    ll res = 1;
    while (n > 0) {
        if (n & 1) res = res * x % mod;
        x = x * x % mod;
        n >>= 1;
    }
    return res;
}

ll gcd(ll x, ll y) {
    if (y == 0) return x;
    return gcd(y, x % y);
}

int main() {
    ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    int N, M;
    cin >> N >> M;
    VI A(M);
    VB B(N + 1, false), C(N + 1, false);
    REP(i, M) {
        cin >> A[i];
        C[A[i]] = true;
    }
    FOR(i, 1, N + 1) B[i] = N / i % 2;
    //FOR(i, 1, N + 1) cout << B[i]; cout << endl;
    //FOR(i, 1, N + 1) cout << C[i]; cout << endl;
    int ans = 0;
    for (int i = N; i > 0; i--) {
        if (B[i] != C[i]) {
            ans++;
            for (int j = 1; j * j <= i; j++) {
                if (i % j) continue;
                C[j] = !C[j];
                if (i / j != j) C[i / j] = !C[i / j];
            }
        }
    }
    cout << ans << endl;
}