#include<fstream>
#define ll long long
using namespace std;
ifstream f("light2.in"); ofstream g("light2.out");
int k,i,p,d[25],x[25];
ll n,nr,mc[25];
ll Euclid(ll a, ll b) 
{	while(b) {ll r=a%b; a=b; b=r;};
    return a;
}
int main()
{   f>>n>>k;
    for(i=1;i<=k;++i) f>>d[i];
    p=1; mc[0]=1;
    while(p)
	{	++x[p];
		if(x[p]<=k)
		{	mc[p]=(d[x[p]]/Euclid(d[x[p]],mc[p - 1]))*mc[p-1];
			if(mc[p]<=n)
			{	ll t=(n/mc[p])*(1LL<<(p-1));
				if(p%2) nr+=t;	else nr-=t;
				x[p+1]=x[p];
				++p;
			}
		}
		else --p;
	}
	g<<nr<<'\n'; g.close(); return 0;
}