#include <fstream>

using namespace std;
ifstream in("ciur.in");
ofstream out("ciur.out");


bool v[2000001];
int c;
int main()
{
    int n,i,j;
    in>>n;
    for(i=0;i<=n;i++)
    {
        in>>v[i];
    }
    for(i=2;i<=n;i++)
    {
        if(v[i]==0)
        {
            c++;
            for(j=i*2;j<=n;j=j+i)
            v[j]=1;
        }

    }
    out<<c;
    return 0;
}