#include <iostream>
#include <vector>
#include <algorithm>
#include <utility>
#include <set>
#include <map>
#include <queue>
using namespace std;
int main()
{
    int N, M;
    cin >> N >> M;
    vector<int> A(M);
    vector<int> temp(N + 1);
    for (int i = 0; i < M; i++)
    {
        cin >> A[i];
        temp[A[i]] = 1;
    }
    vector<int> cnt(N + 1);
    for (int i = 1; i <= N; i++)
    {
        for (int j = i; j <= N; j += i)
            cnt[i]++;
    }
    int ans = 0;
    for (int i = N; i >= 1; i--)
    {
        if (cnt[i] % 2 == temp[i])
            continue;
        else
        {
            ans++;
            for (int j = 1; j * j <= i; j++)
            {
                if (i % j == 0)
                {
                    cnt[j]--;
                    if (j * j != i)
                        cnt[i / j]--;
                }
            }
        }
    }
    cout << ans << endl;
}