#include <bits/stdc++.h>

using namespace std;

typedef unsigned long long ull;

vector<ull> primes(ull maxPrime){
    vector<bool> p(maxPrime + 1, true);

    for(ull i = 2; i <= sqrt(maxPrime + 1); ++i){
        if(p[i]){
            for(ull j = i * 2; j < maxPrime + 1; j += i){
                p[j] = false;
            }
        }
    }

    vector<ull> result;
    for(ull i = 2; i < maxPrime + 1; ++i){
        if(p[i]){
            result.push_back(i);
        }
    }

    return result;
}


int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);

    ull n;
    cin >> n;

    ull topPrime = ceil(cbrt(ceil(n / 2)));
    auto ps = primes(topPrime);

    ull result = 0;

    if(ps.size() < 2){
        cout << result << endl;
        cout << flush;
        return 0;
    }

    for(size_t i = 1; i < ps.size(); ++i){
        ull q = ps[i];

        for(size_t j = 0; j < i; ++j){
            ull p = ps[j];
            ull k = p * q * q * q;

            if(k > n){
                break;
            }
            result++;
        }
    }

    cout << result << endl;

    cout << flush;

    return 0;
}