#include<cstdio>
#include<cstdlib>
#include<ctime>
#include<iostream>
#include<algorithm>
#include<deque>
#include<queue>
#include<set>
#include<vector>
using namespace std;

#define II inline
#define LL long long
#define PII pair<int, int>
#define PDD pair<double, double>
#define fs first
#define sc second
#define mp make_pair
#define pb push_back
#define FOR(i, a, b) 	for(int i = a ; i <= b ; i++)
#define IFOR(i, a, b) 	for(int i = a ; i >= b ; i--)
#define FORIT(it, V) 	for(vector<int> :: iterator it = V.begin() ; it != V.end() ; it++)
#define all(a) a, a + 

const char IN[] = {"light2.in"};
const char OUT[] = {"light2.out"};
const int INF = 1000000005;
const double PI  = 3.14159265;
const LL NMAX = 1LL<<42;
const int KMAX = 25;

LL N;
int K, d[KMAX], lua[KMAX];
int nr = 0;
LL REZ;

void citi()
{
	scanf("%lld", &N);
	scanf("%d", &K);
	FOR(i, 1, K)	scanf("%d", &d[i]);
}

LL cmmdc(LL a, LL b)
{
	LL r;
	while(b)
	{
		r = a % b;
		a = b;
		b = r;
	}
	return a;
}

void back(int k, LL P, int nr)
{
	if(k == K + 1)
	{
		if(nr)
		{
			if(nr&1)	REZ += (1LL<<(nr - 1)) * N/P;
			else		REZ -= (1LL<<(nr - 1)) * N/P;
		}
		return;
	}
	
	back(k + 1, P, nr);
	
	P = P/cmmdc(P, d[k]) * d[k];
	back(k + 1, P, nr + 1);
}

void scrie()
{
	printf("%lld", REZ);
}

int main()
{
	freopen(IN, "r", stdin);
	freopen(OUT, "w", stdout);
	citi();
	back(1, 1, 0);
	scrie();
	return 0;
}