#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); ++i)

using namespace std;
using ll = long long;

// linear sieve
vector<bool> isp;
vector<int> ps, pf;
void sieve(int mx) {
    isp.resize(mx+1);
    pf.resize(mx+1);
    rep(i, mx+1) pf[i] = i;
    for (int i = 2; i <= mx; ++i) {
        if (pf[i] == i) isp[i] = true, ps.push_back(i);
        rep(j, ps.size()) {
            int x = ps[j] * i;
            if (x > mx) break;
            pf[x] = ps[j];
        }
    }
}

int main() {
    sieve(1e7);
    ll n;
    cin >> n;
    
    __int128_t now = 1;
    int ans = 0;
    for (int p : ps) {
        if (now*p > n) break;
        now *= p;
        ans++;
    }
    
    cout << ans << '\n';
    
    return 0;
}