#include <bits/stdc++.h>

using namespace std;
typedef unsigned long long ll;

int main()
{
    ll n;
	cin >> n;
	
	vector<ll> primes;
	primes.push_back(2);
	ll x = 1;
	ll xanterior = 0;
	
	if(n == 2 || n == 3)
	    cout << 1 << endl;
	
	for(ll i = 3; i < n + 1; i++){
		
		if(x != xanterior){
			ll j = 0;
			ll product = 1;
			for(; j < x; j++)
				product *= primes[j];
			//cout << product << endl;
			if(product > n){
				cout << j - 1 << endl;
				break;
			}else if(product == n){
				cout << j << endl;
				break;
			}
		}
		
		ll primo = 1;
		for(ll j = 0; j < x; j++){
			if(i % primes[j] == 0){
				primo = 0;
				break;
			}
		}
		
		xanterior = x;
		
		if(primo){
			primes.push_back(i);
		    x++;
		}
	}
	
}