#include <iostream>
#include <cstdio>
#include <cstring>
#include <vector>
#include <string>
#include <algorithm>
#include <queue>
using namespace std;
typedef long long ll;
int n,m;
vector<int> num;
int gcd(int a,int b){
    if(b==0) return a;
    return gcd(b,a%b);
}
int Lcm(int a,int b){
    return a/gcd(a,b)*b;
}
void solve(){
    vector<int> dig;
    int ans = 0;
    for(int i = 1; i < (1<<m); i++){
        dig.clear();
        for(int j = 0; j < m; j++){
            if(i & (1<<j)) dig.push_back(j);
        }
        int t = 1;
        for(int j = 0; j < dig.size(); j++){
            t = Lcm(t,num[dig[j]]);
        }
        if(dig.size()%2==0) ans -= n/t;
        else ans += n/t;
    }
    cout<<ans<<endl;
}
int main(){

    while(~scanf("%d%d",&n,&m)){
        n--;
        num.clear();
        int tn;
        for(int i = 0; i < m; i++){
            scanf("%d",&tn);
            if(tn!=0) num.push_back(tn);
        }
        m = num.size();
        solve();

    }
    return 0;
}