//  Prime Multiples

#include<bits/stdc++.h>

using namespace std;
using ll = long long;

int main() {
    ll n, k;
    cin >> n >> k;
    vector<ll> primes(k);
    for (auto &e: primes) cin >> e;

    ll ans = 0;
    for (ll i = 1; i < (1 << k); i++) {
        ll prime_product = 1;
        for (ll j = 0; j < k; j++) {
            if ( i & (1 << j)) {
                if (prime_product > n / primes[j]) {
                    prime_product = n + 1;
                    break;
                }
                prime_product *= primes[j];
            }
        }
        if (__builtin_popcount(i) & 1) {
            ans += n / prime_product;
        } else {
            ans -= n / prime_product;
        }
    }
    cout << ans << endl;
    return 0;
}