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

typedef long long ll;
ll n, k;

ll mdc(ll a, ll b){
	if(!b) return a;
	return mdc(b, a % b);
}

ll mmc(ll a, ll b){
	return a*b/mdc(a, b);
}

int main(int argc, char const *argv[])
{
	scanf("%lld %lld", &n, &k);
	vector<ll> v(k);
	for(int i = 0; i < k; i++)
		scanf("%lld", &v[i]);

	ll ans = 0;
	for(int b = 1; b < (1 << k); b++){
		vector<ll> a;
		for(int i = 0; i < k; i++)
			if(b & (1 << i))
				a.push_back(v[i]);

		ll x = 1;
		for(int i = 0; i < a.size(); i++)
			x = mmc(x, a[i]);
		if(a.size() % 2)
			ans += n/x;
		else
			ans -= n/x;
	}

	printf("%lld\n", n - ans);

	return 0;
}