#include <bits/stdc++.h>

using namespace std;

ifstream fin("cubprim.in");
ofstream fout("cubprim.out");
int n, a[200005],k;
bitset <4200002> b;
void Ciur()
{
    int i, j;
    b[1] = b[0] = 1;
    for (i = 4; i * i <= 4200000; i += 2)
        b[i] = 1;
    for (i = 3; i * i <= 4200000; i += 2)
        if (b[i] == 0)
            for (j = i * i; j <= 4200000; j += 2 * i)
                b[j] = 1;
    for (i = 2; i <= 4200000; i++)
        if (b[i] == 0) k++;
    cout << k;
}
int main()
{
    int i,j;
    Ciur();
    fin >> n;
    for (i = 1; i <= n; i++)
        fin >> a[i];



    return 0;
}