#include <bits/stdc++.h>
#define ll long long
#define endl '\n'
#define task ""
#define int ll
using namespace std;

signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    if (fopen(task".inp", "r"))
    {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    int n, k; cin >> n >> k;
    set <int> s;
    for (int i = 1; i <= k; ++i)
    {
        int b; cin >> b; s.insert(b);
    }
    vector <int> a;
    a.push_back(0);
    for (auto i : s) a.push_back(i);
    int q = a.size() - 1;
    if (a[1] == 1)
    {
        cout << n; return 0;
    }
    vector <vector<int>> v (q + 1);
    v[0].push_back(1);
    for (int i = 1; i <= q; ++i)
    {
        for (int j = i; j >= 1; --j)
            for(auto p : v[j - 1])
                if (p / __gcd(p, a[i]) * a[i] <= n) v[j].push_back(p / __gcd(p, a[i]) * a[i]);
    }
    int ans = 0;
    for (int i = 1; i <= q; ++i)
    {
        for (auto p : v[i])
        {
            if (i & 1) ans += n / p;
            else ans -= n / p;
        }
    }
    cout << ans;
    return 0;
}