#include <bits/stdc++.h>

using namespace std;
void fast_io() {
    ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
}
int main() {
    fast_io();
    vector<long long> primes = {
        2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59,
    };
    long long n;
    cin >> n;
    int ans = 0;
    long long cur = 1;
    for (long long p : primes) {
        if (cur <= n / p) {
            cur *= p;
            ans++;
        } else {
            break;
        }
    }
    cout << ans << endl;
}