#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;

#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
#define rep(i,a,b) for (int i = (a); i < (b); ++i)

mt19937 rng(random_device {}());

struct Sieve {
    vi primes, spf;
    Sieve(int n) : spf(n) {
        rep(i, 2, n) {
            if (!spf[i]) {
                spf[i] = i;
                primes.push_back(i);
            }
            for (int j : primes) {
                if (j * i >= n) break;
                spf[i * j] = j;
                if (j == spf[i]) break;
            }
        }
    }
};

int main()
{
    cin.tie(0)->sync_with_stdio(0);

    ll n;
    cin >> n;
    Sieve s(100);
    ll p = 1;
    int ans = 0;
    for(auto v : s.primes){
        if(p <= n/v){
            p *= v;
            ans++;
        }else break;
    }

    cout << ans << endl;

    return 0;
}