#include <iostream>
#include <fstream>
using namespace std;
ifstream in("ciur.in");
ofstream out("ciur.out");
bool v[2000001];
int gg;
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)
           {
            gg++;
            for(j=i*2;j<=n;j=j+i)
            v[j]=1;
           }
    }
    out <<gg;
    in.close();
    out.close();
    return 0;
}