#include<iostream>
#include<cstdio>
#include<cmath>
#include<string>
#include<queue>
#include<algorithm>
#include<stack>
#include<cstring>
#include<vector>
#include<list>
#include<set>
#include<map>
using namespace std;
#define ll __int64
#define mod 1000000007
#define inf 999999999
//#pragma comment(linker, "/STACK:102400000,102400000")
int scan()
{
    int res = 0 , ch ;
    while( !( ( ch = getchar() ) >= ‘0‘ && ch <= ‘9‘ ) )
    {
        if( ch == EOF ) return 1 << 30 ;
    }
    res = ch - ‘0‘ ;
    while( ( ch = getchar() ) >= ‘0‘ && ch <= ‘9‘ )
        res = res * 10 + ( ch - ‘0‘ ) ;
    return res ;
}
ll a[110];
ll ji;
ll ans,x,y;
ll gcd(ll x,ll y)
{
    return y==0?x:gcd(y,x%y);
}
void dfs(ll lcm,ll pos,ll step)
{
    if(lcm>x)
    return;
    if(pos==ji)
    {
        if(step==0)
            return;
        if(step&1)
        ans+=x/lcm;
        else
        ans-=x/lcm;
        return;
    }
    dfs(lcm,pos+1,step);
    dfs(lcm/gcd(a[pos],lcm)*a[pos],pos+1,step+1);
}
int main()
{
    ll z,i,t;
    while(~scanf("%I64d%I64d",&x,&y))
    {
        x--;
        ji=0;
        for(i=0;i<y;i++)
        {
            scanf("%I64d",&z);
            if(z==0)continue;
            a[ji++]=z;
        }
        ans=0;
        dfs(1,0,0);
        printf("%I64d\n",ans);
    }
    return 0;
}