#include <cstdio>
#include <bitset>

//EIUCLAP

//consts
const int KMAX=22;

using namespace std;

int main(){
	freopen("light2.in","r",stdin);
	freopen("light2.out","w",stdout);
	
	//vars
	unsigned char k;
	int n;
	int v[KMAX];
	int sol=0;
	unsigned char i,j;//cycle
	
	//read
	scanf("%d%hu",&n,&k);
	for(i=0;i<k;++i){
		scanf("%d",&v[i]);
		sol+=n/v[i];
		for(j=0;j<i;++j)
			sol-=2*n/(v[j]*v[i]);
	}
	
	printf("%d\n",sol);
	
	return 0;
}