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