using namespace std;
#include<iostream>
#include<fstream>
#include<bitset>
ofstream fout("light2.out");

int N,K,d[30];
int a[10000000];

void cit()
{
    ifstream fin("light2.in");
    int ans=0;
    fin>>N;
    fin>>K;
    int din;
    int i;
    for(i=1;i<=K;i++)
    {
        fin>>d[i];
        din=d[i];
        while(din<=N)
        {
            a[din]=a[din]?0:1;
            din+=d[i];
        }
    }

    for(i=1;i<=N;i++)
    {
        if(a[i]==1)
          ans++;
    }

    fout<<ans<<"\n";
    fin.close();

}

int main()
{
    cit();

    fout.close();
    return 0;
}