#include <cstdio>

#define file_in "light2.in"
#define file_out "light2.out"

int N,v[10100000],K,X,ans,i;

int main(){
	
	freopen(file_in,"r",stdin);
	freopen(file_out,"w",stdout);
	
	scanf("%d", &N);
	for (i=1;i<=N;++i) v[i]=1;
	scanf("%d", &K);
	while(K--){
		scanf("%d",&X);
		i=X;
		while(i<=N){
			v[i]^=1;
			i+=X;
		}
	}
	ans=0;
	for (i=1;i<=N;++i)
		 if (!v[i]) ans++;
	
    printf("%d\n", ans);
	
	return 0;

}