#include<fstream>
#define ll long long
using namespace std;
ifstream f("light2.in");
ofstream g("light2.out");
ll i,n,k,sol,d[30];
ll gcd(ll a,ll b)
{
    if(b==0)
    return a;
    return gcd(b,a%b);
}
void rez(ll p,ll x,ll s,ll put2)
{
    ll y;
    for(ll i=p+1;i<=k;++i)
    {
        y=x*d[i]/gcd(x,d[i]);
        sol+=n*s*put2/y;
        rez(i,y,-s,2*put2);
    }
}
int main()
{
    f>>n>>k;
    for(i=1;i<=k;++i)
    {
        f>>d[i];
    }
    for(i=1;i<=k;++i)
    {
        sol+=n/d[i];
        rez(i,d[i],-1,2);
    }
    g<<sol<<'\n';
    return 0;
}