#include <fstream>
#define nmax 32

using namespace std;

ifstream in("light2.in");
ofstream out("light2.out");

long long i,nrcom,Sol,prod,N;
int K,V[nmax],nr,j;

int main()
{
    in>>N>>K;
    for(i=1;i<=K;i++)in>>V[i];
    nrcom = (1<<K)-1;
    for(i=1;i<=nrcom;i++)
    {
        prod = 1,nr=0;
        for(j=0;j<K;j++)
            if(i&(1<<j))
                prod*=V[j+1],nr++;
        if(nr&1)Sol+=(N/prod);
        else Sol-=2*(N/prod);
    }
    out<<Sol;
    return 0;
}