#include <iostream>
#include <cmath>

using namespace std;

int main() {
    std::ios_base::sync_with_stdio(0);
    unsigned long long n, counter = 0;
    cin >> n;
    while(n != 0)
    {
        double gg = sqrt(n);
        for(int i = 2; i <= gg; i++)
        {
            gg = sqrt(n);
            if(gg < 2) break;
            if(n % i == 0)\
            {
                n /= (n / i);
                counter++;
                i = 1;
            }
        }
        counter++;
        n--;
    }
    cout << counter;
}