#include<iostream.h>
#include<fstream.h>
long long n,a[100];
int viz[100];
int main()
{int z=0,i,j,k;
ifstream f("light2.in");
ofstream h("light2.out");
f>>n;
f>>k;
for(i=1;i<=k;i++)
	f>>a[i];
for(i=2;i<=n;i++)
for(j=1;j<=k;j++)
if(i%a[j]==0&&viz[i]%2==0)
	{z++;
viz[i]=viz[i]+1;}
else
if(i%a[j]==0&&viz[i]%2!=0)
{z--;
viz[i]=viz[i]+1;}
h<<z;
return 0;}