#include <cstdio>

#include <cstring>

#include <iostream>

#include <algorithm>

using namespace std;

typedef long long ll;

ll n, m, a[], ans;

ll gcd(ll a, ll b)

{

    if (!b)

        return a;

    return gcd(b, a % b);

}

void dfs(int dep, int cnt, ll lcm)

{

    if (dep == m + )

    {

        if (cnt & )

            ans += (n / lcm);

        else

            if (cnt)

            ans -= (n / lcm);

        return;

    }

    dfs(dep + , cnt, lcm);

    ll temp = lcm / gcd(lcm, a[dep]) * a[dep];

    dfs(dep + , cnt + , temp);

}

int main()

{

    scanf("%lld%lld", &n, &m);

    for (int i = ; i <= m; i++)

        scanf("%lld", &a[i]);

    dfs(, , );

    printf("%d\n", n - ans);

    return ;

}